The Sentry is the Engineer's primary contribution to the war effort, and knowing a few things about how and where to place it, and how to care for it, will go a long way to keeping it, you, and your team alive.



First, let's talk placement.


Sentries provide a huge amount of firepower; at Level 3, they're capable of automatically firing two weapons at once with aimbot accuracy. As a result, they are most useful when they can shoot at the robots constantly - from the moment they spawn to the moment they die.

This means your Sentry does no good if it's placed all the way back at the bomb hatch, while the rest of your team is up at the front. It's not providing security, it's not providing a last line of defense, it's simply a wealth of firepower that could be killing robots that currently isn't. Your Sentry needs to be up at the front lines, covering the path that the robots will take. Watch the blue arrows before a wave starts, and make sure your Sentry is covering the correct path - your Sentry does no good to anyone if the robots aren't going to walk into its line of fire!

This is not to say you shouldn't move your Sentry back periodically. If things go bad due to poor team composition, bad play, or simple misfortune, you could find your Sentry position overrun. It's a good idea to move your Sentry back to a more secure location right before you think that's going to happen. Do not move it all the way back, however, unless there are robots directly threatening the hatch.

When picking a spot to set up, choose a location for your Sentry that is defensible, but also offers it a clear field of fire to shoot at the robots. High ground is almost always a good choice, but be aware that you can body-block robots with your Sentry if you can cover a chokepoint - this is particularly important for Giant Scouts. Just don't try this with Sentry Busters (see below) or Tank Robots - the latter can crush any building on contact, even a Sentry.

Of course, proper Sentry placement is only one third of the Sentry equation. Next, let's discuss...


Most engineers have two options regarding using the Sentry: autopilot, and Wrangling. There are two things to consider when it comes to choosing which mode your Sentry should be in. Enemy mobility, and enemy firepower.

For faster enemies that either die quickly or have a hard time reaching you, like scouts and pyros, your Sentry is best left on autopilot. Its aim is probably better than yours, and it has enough firepower to gun down robots rapidly, even without the firing speed boost from the Wrangler. You should focus on either maintaining the Sentry, or maybe using the Shotgun or Frontier Justice to take potshots at the robots yourself - just don't expose yourself to enemy fire. If you have the Rescue Ranger, use it to repair your Dispenser (more on that later.) Fast robots usually don't present much of a threat to you or your Sentry if your placement is good and the rest of the team does their jobs.

Durable enemies with higher firepower, like Tanks and any Giant Robot, are a different story. When these show up, consider Wrangling the Sentry, putting yourself in a high position with a good view of the incoming robots, and use the Wrangler to focus on these threats before they become a problem. The Wrangler's shield reduces damage on your Sentry by about two-thirds, and the increased fire rate will destroy enemies much, much faster than normal. If you're very, very confident in your Wrangling skills, remember that the Sentry rockets have knockback. You can use this to knock robots off their path and into pits to buy time for you and your team. Use the Wrangler, or pick up your Sentry, if there are active Ubermedics in the field - you do not want to let the Sentry trigger an Ubercharge with its autofire.

With Tanks in particular, examine the situation. You have to reposition your buildings a lot to deal with this. Is there enough DPS on the tank to kill it before it reaches the hatch? Then put your Sentry in a spot where it can help suppress the robots while you move the Dispenser to keep the tankbusters filled. Is the tank not dropping fast enough? Then keep your Sentry on the tank, wrangling it between Dispenser moves.

It's important to know when not to Wrangle your Sentry. There's an easy rule to this: keeping your gun firing is more important than maximizing your damage-per-second. Sentries, even without the Wrangler, can still kick a lot of robot behind on their own. If your gun needs maintenance, it's more important to fix it up than it is to keep it Wrangled - the Wrangler does you no good if the gun's empty or getting wrecked. If you are ever in doubt, use autopilot.

So you know where to set up, and what to do when you get there. Now you just need to know how to...


If you're new to the game entirely, or just never played Engineer before, realize that Sentries do not have unlimited ammunition and are not disposable. You need to stay with your Sentry Gun and maintain it. Whacking your Sentry with your wrench will repair damage and reload both types of ammunition, at the cost of metal. Watch your Building HUD, and make sure to keep it topped off and fixed up whenever you can. A Sentry that is clicking rapidly because its guns are dry only possesses a fraction of the firepower of a fully-loaded one - avoid this situation if it is at all possible. It can get a bit more complicated than that, though.

Now you might be chuckling here and thinking, "hit it with your Wrench, what more is there to understand?" It's a bit more difficult than that in Mann vs. Machine - you typically don't have just one to three guys firing at you, you've got a whole robot swarm. If you expose yourself to fire unnecessarily when trying to fix your gun, you will get shot to hell, and so will your Sentry as soon as you die. There are four strategies when it comes to Sentry maintanenace, each suited to different situations. A good Engineer will pick the right strategy for the current situation.

First, hiding behind the Sentry. This works against bullet weapons: Miniguns, Sniper Rifles, Scatterguns. The Sentry will block incoming fire, and you can just whack it with the wrench to fix the damage. If things get hairy, Wrangle your Sentry for a moment to get the Sentry shield, then switch back to the wrench. The Sentry will go inactive for a moment, but it will keep the shield for a little while too, giving you a chance to fix it up. Remember to crouch if your Sentry is level with you; you're taller than your Sentry and enemies can shoot you over it.

If you're under fire from explosives, you don't want to try to just wrench the building, Wrangler-shield or not. The explosive splash will probably kill you. If you are carrying the Rescue Ranger, use that instead to keep the Sentry fixed until there's a break in the explosions.

There may be situations where you don't have the Rescue Ranger, or there's just so much incoming fire that no amount of Wrangling or repair will save your Sentry. This is where you pull back. If you find you or your Sentry taking too much fire to keep up with, pick up the Sentry and step back into cover, fix it up there, then put it back.

Using the Dispenser in MvM is probably the single biggest difference from standard play. It takes a very different mindset to understand Dispenser placement in MvM.








So, let's start off with the first and most important point to understand...


You might be thinking "What are you SMOKING?! How am I going to get metal?" Well my friend, that's what ammo pickups are for. You might be surprised to find out that the developers at Valve were pretty good about putting ammo pickups near places where you want to set up a Sentry. As a result, if you picked a good position for your Sentry, a supply of metal that replenishes much faster than a Dispenser is usually only a couple steps away, you merely have to go and get it.

Furthermore, there are two upgrades that Engineers have that can make even that less necessary. Those are Metal Capacity (under the Sentry Gun tab) and Metal Regeneration (under the Self tab). Consider upgrading them when you have the credits to spare from more important upgrades, like Building Health, Sentry Firing Speed, and Dispenser Range.

Building a Sentry nest and humping your Dispenser while whacking your Sentry with your wrench like a bot just deprives the rest of the team of the benefits of a Dispenser. And trust me, buddy...


Imagine, if you will, a Heavy Weapons Guy that never has to stop shooting. It's kinda like having a second Sentry, yes? Now imagine Pyro that can retreat to cover, quickly heal and reload, and then rush back out to roast things, or who can torch a Tank in record time because he doesn't have to spend time grabbing ammo. Or a Soldier that can launch rocket after rocket like he was shooting layups back in Podunk.

These things, my friend, are all possible with a convenient Dispenser. Always remember the Australium Rule: In MvM, what you can do for your team is far more important than what you can do for you. Putting your Dispenser in a place where your team can leverage it can make a bad team passable, and turn a good team into a brick-wall defense that stuffs the robots back into their spawn and mails them back to Gray Mann with a three page letter on why he sucks.

So you might be asking...


There are three considerations when placing your Dispenser - cover, accessibility, and retrievability.

Cover is pretty self-explanatory. You want to put your Dispenser in a place where it will not get shot. Behind corners or walls is usually good. Inside structures is even better provided you do not compromise accessibility in the process. Remember, Dispensers Help The Team; if your team can't reach the Dispenser within five seconds of needing it, chances are you need a better spot.

Accessibility is a bit more complex. You want your Dispenser in a place where other teammates can use it quickly. Particularly Soldiers, Demomen, Heavies, and Pyros - they have the most ammo problems and need to be on the front lines constantly do deal good damage. Scouts and Snipers can usually get by on ammo pickups due to their mobility or distance from the battlefield respectively, and Spies seldom even use an ammo-requiring weapon.

Retrievability refers to your ability to repair and move the Dispenser. Remember how I mentioned the Rescue Ranger earlier? This is where it shines. Dispensers don't need reloading like a Sentry does, so if you put your Dispenser in a place where you have a clean line of fire to it, you can quickly repair it in combat by shooting it with the Rescue Ranger's repair claws. In addition, you can quickly retrieve it if it needs to be moved by using the Rescue Ranger's alt-fire. Manually pick up and haul your Sentry, when retreating, then step out and use the RR to grab your Dispenser to quickly set up a chokepoint in a new location.

If you're ever unsure where to put a Dispenser, talk with your team. Ask them where they're gonna be, and what they're gonna be doing during the wave. Ask 'em if there's any place they'd particularly like a Dispenser. Good engineers work with their teammates. If they don't give you any advice, just try to keep it near where the bulk of ammo-heavy classes are fighting, keeping in mind the three principles I've explained. Don't forget to move it if the battle-lines shift, such as pursuing a rolling tank.

On that note, you should consider upgrading...


Dispenser range is an invaluable upgrade, but in general play it's a lower priority than Building Health. On higher-skilled teams, those that actually make use of it and protect your buildings, it's worth prioritizing more highly. If you have to choose between this and Sentry Firing Speed, usually I find that the Dispenser is a better investment, unless the team is undermanned or under-gunned (too many Snipers, Pyros, or Spies, not enough Heavies, Soldiers, or Demomen.)

Your Teleporters are an indispensible, yet thankfully very low-maintenance piece of kit. They're very easy to handle and there's only a few considerations you should have to think about when setting them up.








First and foremost is the answer to the question:


Your Teleporter Entrance goes at spawn. No question about it. If there's one spawn door everyone uses, put it outside that door. If there's two doors that are used equally, put the Teleporter midway between them. Make sure people see it the moment they exit the door, so even the most oblivious players know it's there. Keep your Teleporter back, so that it's less likely to get shot at in the unfortunate event the robots make it to the bomb hatch.

The Teleporter exit is a bit more complex. You want it close to the front lines so that people coming out of spawn can instantly reinforce the front. You also want it to be somewhere where it's not on the robot travel path, so that robots don't blow it up as they walk past.

You also want to make sure people are not disoriented coming out of the Teleporter. Pay attention to the exit direction of your Teleporter; do not place a Teleporter facing a wall. Try to place your Teleporters so that players exit facing the most convenient path to get back to the battlefield, that way even the dumbest W+M1 Pyro can hurl himself or herself back into the fray quickly. Remember that you can rotate a Teleporter, or any building, 90 degrees clockwise as many times as you want by using the alt-fire key when placing the blueprint.

There will be situations where you might have to consider...


In most cases, either your Teleporters will not need to be moved unless you lose a wave and need to rebuild them, or it will be far too unsafe to retrieve a Teleporter exit and move it. Once your Teleporters are up at the beginning of a wave, chances are you can safely forget about them.

In the event you do need to move or rebuild a Teleporter mid-wave, do so quickly, and don't worry too much about effective placement. Just get it into a useful position quickly, and get back to caring for your Sentry and Dispenser. If people complain, remind them that you're a bit busy with more important things, like making sure your Sentry isn't exploded and that the Dispenser's in a good location to maintain a chokepoint. If you've been following the rest of this guide thus far, you're already doing more for 'em than some Engineers ever manage. If necessary, refine your Teleporter's placement later when you can catch a breather, and definitely place it back up at the front between waves.

Of course, there's always the chance you'll run into...


If there are multiple engineers on your team, see where the other guys set up their Teleporters. Chances are there will be a bunch of Teleporters at spawn, and the other ends at the Engineer's Sentry nest. There's nothing wrong with doing the same, but it can sometimes be useful to set up your entrance at the other guys' exit, and then create a network of Teleporters between Sentry locations. Coordination and collaboration are key here - don't try this with people who aren't willing to work with you.

Now on the subject of Teleporter networks, you might be asking yourself if you should use...


In most cases, the two-way Teleporter upgrade is not necessary. It can be convenient for getting back to spawn between waves, and it can save a wave if a giant scout grabs the bomb and starts running, but typically it won't be needed. Unless you know a wave coming up will require the upgrade, consider it extremely low-priority.

Okay, you know how your buildings work. But how do you keep them safe from the nastier robots that specialize in dismantling Engineers, namely Sentry Busters and Spies? Well, here's how to do that.













Let's start with the obvious threat...


These things are intimidating. They're giant fast-moving naval mines on legs that exists for one purpose - to run up to your Sentry and explode. They start to spawn any time your Sentry deals too much damage to the robot horde (15 kills or 3000 damage, whichever comes first), and they keep spawning again and again until the offending Sentry is destroyed by any means, including self-destruct. At that point, the counter resets and they stop spawning until another Sentry hits the requirement. Sentry Busters have their own spawn schedule which is separate from the regular robots; they won't necessarily accompany other enemies. They're pretty tough, requiring combined fire from multiple teammates to bring down (2500 HP). They present two dangers to your buildings - crushing and explosion.

Sentry Busters are considered Giant Robots. This means you cannot knock them back (although you can delay them by hitting them with sufficient knockback). Sentry Busters can also destroy Dispensers and Teleporters by running over them. Try to place your Dispenser and Teleporters in places where they won't get stepped on. Sentry Busters typically take the most direct route from the robot path to your Sentry, so make sure your other buildings are not too close to that path.

The primary threat of the Sentry Buster is its explosion, and it takes a specific technique to save your Sentry Gun in the event of a Buster approaching. When you see a Buster, watch it like a hawk. When it gets close, pack up your building and lure the Sentry Buster away from your teammates and other buildings. Wait for it to run up to you, watch for it to squat and start beeping faster, and when it does run like hell. If you did it right, you should be able to get just outside the blast radius before the Sentry Buster explodes, and you'll earn the Real Steal achievement if it's your first time doing it successfully. Get used to doing this - you cannot count on your team to always kill the Sentry Busters for you. It's nice if they do, but don't count on it. They have enough to worry about with the normal robots. Note that, if your teammates do take down a Sentry Buster, it will STILL squat and explode on the spot, so be careful.

For the ballsier Engineers out there, on maps like Decoy and Mannhattan where Sentry Busters can be made to take long, circuitous routes, there's a second strategy for dealing with Busters. Pick up your Sentry, walk out and touch the Buster as it approaches, then quickly spin 180 and run back to your Sentry spot. Touching the Buster while carrying your Sentry will cause it to detonate early, allowing you to escape and put the Sentry back sooner. This means less interruption in your Sentry's firing. Not something I'd recommend for those new to Engineer, but it is an option.

Keep in mind that Sentry Buster explosions can destroy other robots and your teammates. If you absolutely know you can't save the Sentry, then haul your building into a horde of Robots and sacrifice them to the Sentry Buster. Whatever you do, do NOT allow Sentry Busters to blow up your team. Keep your Sentry away from where your teammates are fighting, so that an exploding Buster does not harm them. In addition, keep your Sentry away from other buildings, especially the buildings of other Engineers, so that the Sentry Buster doesn't blow them up even if you save your own. Warn your teammates where you're going to blow the Buster, so they know to stay away.

Now for the slightly more subtle threat...


Spy Robots are far less of a threat than normal spies, as Spy Robots are much less subtle. Just be aware that they do not spawn from normal robot locations, and that they come in groups. Spy robots always come from your spawn, just like players, so if you see a curious duplicate of another player that isn't firing his weapon, and is approaching one of your buildings, call the spy and shoot at it.

When you hear a Spy warning from the Administrator, look over your shoulder every couple seconds. If you've been following my advice and set up your Sentry away from the other players, there should be no excuse for anyone but you to come up to your Sentry spot. If someone does, they're a spy robot and you should smack them with your wrench or shoot them dead.

Spy robots prioritize backstabbing over sapping. They generally won't sap a building unless no players are nearby to stab. Don't let your guard down until the Administrator says that all the spy robots are destroyed, and the Spy icon stops flashing and vanishes from the wave progress indicator.

Dunno if someone's really one of the clankers? Keep a checklist in your mind of safe behaviors and suspicious behaviors, and quickly go through it when you see someone in a place they shouldn't be. Remember that the Administrator will warn you when Spies are on the field, and there will be a flashing warning icon below the progress bar if there are Spies left.

Safe behaviors include attacking with any weapon, a Scout moving at Scout speed, facing the incoming robots, moving towards the incoming robots, using canteens, any form of blast-jumping, staying near your Dspenser without staring at it. The more of these a player is doing, the more likely they are to be legit. Some actions, like moving at Scout speed, using canteens or attacking robots, are foolproof ways to determine if a person is legit, since Spy robots either cannot do these actions, or will lose their disguise if they do.

Unsafe behaviors include not attacking, Scouts moving too slowly and not double-jumping, staring at other players, moving into melee range with other players unnecessarily (the only person who should be at melee range with another player is a Soldier with the Disciplinary Action), staring at your dispenser while standing near it, walking around behind other players without obvious reason, and having the same name/cosmetics as another player. Also, count the number of players you can see - if you count more than the number of players in the game minus one, the difference is made up of Spies. If there's six players, and you can see seven, there's two Spies out there.

At some point or another, you're going to have to pull back. Knowing when and how to do so is an important skill, and one of the hardest skills to master as an Engineer. Any Engineer can hold a position if the team is still fighting - a good one knows when to fall back to more secure locations as necessary.






An Engineer may be three guns and a perpetual ammo and health refill all at once, but he can't do everything. You need to be able to rely on your team to kill the robots your Sentry can't, and without a team your Dispenser and Teleporters are just a waste of metal.

So what happens when the rest of these chuckleheads get themselves killed, through no fault of your own? Well, ideally you'll be falling back to a better location, before the robots swarm up to your Sentry and overrun you. Sometimes, you may notice your team falling back before the robot horde, without getting killed - contrary to what you might think, this is a sign of a good team. You'll want to fall back in this case as well, but use your teammates as cover, and prepare to support them immediately.

Unfortunately, no matter what the situation, there comes a point where you realize you only got two hands and you need both of 'em to carry a building. So that begs the question...


Well, ideally the answer is "all of 'em" but this usually isn't going to happen. You need to prioritize your buildings. It's as much an art as it is a science, and there's a couple different schools of thought.

Sentry First: Proponents of the Sentry-first line of thought make a couple valid points. If you're falling back, it's usually because your team is dead. An unattended autofiring Sentry left at the frontlines could cause you to miss a lot of money before it gets destroyed or rescued. Grabbing the Sentry first stops this from being a problem, as it's the first building to be moved to the new chokepoint you're setting up.

This is usually the safer choice - by the time your team respawns, you should be establishing a new chokepoint with your Sentry and either have already rescued your Dispenser, or be working on a fresh Dispenser for them to use. They can immediately step back into the fray and hold the robots at the new chokepoint, giving you time to potentially grab the teleporter exit and move it, if necessary.

Dispenser First: Proponents of the Dispenser-first line of thought adhere to the Australium Rule: what you do for your team is more important than what you do for yourself. Holding or losing a front line can sometimes hinge on whether a Dispenser is present, and a Sentry is not a substitute for a good team.

This is a bit more risky - it's a lot harder to establish a chokepoint without your Sentry backing you up, and leaving a sentry unattended while you save the Dispenser may cause money to drop behind the Robot lines, where you can't effectively get to it. Sometimes, it can be worth the risk if necessary to save a wave.

If your team falls back in an orderly fashion, collecting money as they go, this is less of a problem. You probably don't have to fall back as far, and keeping them supplied is more important to prevent an overrun. Ideally, your Sentry should be a bit behind the lines anyway, so any money dropped should be retrievable.

Situational Awareness First: I personally follow this line of thought. When you need to fall back, look at you team. Are they dead, or about to be dead? Are robots getting past them? Is the bomb carrier past them? Or are they holding off the horde, giving ground slowly, and keeping the bomb carrier killed?

If it's the former, and the current situation is a loss, grab the Sentry. Move it to a chokepoint where it can intercept the bomb carrier. Gun him down (wrangle if you have to), then use the Sentry to keep the bomb immobile while you either retrieve your Dispenser, or blow the Dispenser and build a new one. By the time the Dispenser's ready, your team should have respawned and should be returning to the new chokepoint you've set up.

If it's the latter, and your Scout's doing a good job of collecting money, you have a little more breathing room. Relocate your Sentry to a point where you can retrieve it, but where it CANNOT fire on the robots - this stops it from accidentally causing money to drop behind robot lines. Optionally, blow the Sentry for the same reason, if you can't relocate it or don't have time. Grab your Dispenser and put it in a spot where it can support the team, and then either retrieve or rebuild the Sentry to provide covering fire.

Whatever you decide to do in these situations, do it quickly, smartly, and in an orderly fashion. If you screw up, the entire team's gonna feel it, and this is the point where you are the most vulnerable. Mentally go over your preferred exit strategy before a wave starts, maybe even practice it a couple times if your team isn't readying up. You can never be too well-prepared. Speaking of preparedness...


Respawn, duh.

In all seriousness, if you die chances are your buildings are going to follow suit. Whatever killed you is probably not going to stop shooting your buildings. Before leaving spawn, if credits allow, consider grabbing an upgrade canteen to help yourself set back up more quickly.

Get back to your team and set up your buildings as quickly as possible, prioritizing the Sentry or Dispenser based on what the team needs most - firepower or supplies. If you have an upgrade canteen, drop both buildings and hit the canteen to instantly fortify the area.

If you die and your buildings don't, retrieve them if you can do so without risking another death. If your team has fallen back while you were dead, quickly retrieve or blow the Sentry first so it doesn't cause you to lose credits. If they held the front while you were respawning, leave the buildings alive and in place so that they can continue supporting the front.


The teleporter is a convenience - nothing more. If your teleporter has been overrun, don't take risks to grab it, especially not if more important buildings haven't been properly rescued. If the teleporter exit is destroyed, and you've rescued/rebuilt the Sentry and Dispenser, drop the teleporter exit behind you and let it auto-construct while you're maintaining your other buildings. The further you get pushed back, the less necessary a teleporter is.

If the frontlines get overrun, but the teleporter is not destroyed, consider blowing it yourself. It's better to blow the teleporter exit than to allow teammates to teleport behind the enemy lines and get mowed down. At the very least, warn them that the teleporter's not safe.

As an Engineer, you have a lot of choices. Some of these are better than others. Here's some suggestions on what to bring to a robot brawl, and what to leave on the gun rack back home. Keep in mind, these are my opinions and suggestions - consider them guidelines, not hard-and-fast rules.

First up, let's talk...

Stock Shotgun: Well if you haven't got anything else, this'll at least let you defend yourself from spies and maybe pepper a few robots alongside your Sentry. I don't recommend relying on it for anything else.

Frontier Justice: You shouldn't be in the habit of letting your Sentry get destroyed. If you do find yourself losing it frequently, equip the Jag alongside this to help yourself rebuild it faster, and use the revenge-crits to punish robots for destroying your structures. A useful strategy with the FJ is to blow and replace your Sentry deliberately between waves, or during quiet moments if you've got more Upgrade Canteens than you need, or sufficient time to rebuild and re-upgrade manually. This gives you revenge crits at no risk.

Pomson 6000: Spy robots rarely use their cloaking ability, and Ubermedics are rare and often better handled by killing them with burst damage. If your team has no way to deal with Ubermedics, you can disrupt them with this, but it's really the job of the Demo, Soldier, Sniper, Spy or Pyro.

Widowmaker: If you're gonna go combat-Engineer, this is probably your best choice. Getting Projectile Penetration, jacking up Metal Capacity early, and having steady aim and dodging skills will let you recover more metal than you shoot overall. If your aim's shaky, or you aren't good at direct combat, give it a pass.

Rescue Ranger: It provides long-distance repairs for your Dispenser, and lets you safely repair your Sentry without getting splashed by explosives. You can save a building from any range, giving you breathing room in the event of Sentry Busters. It's not great for shooting robots on your own, but then again, that's what your buildings are for.

Next up are...

Stock Pistol: Probably your worst secondary choice. You can upgrade it to have a ridiculous fire rate and its ammo reserve is huge, but if you're plinking with a pistol then you're shirking your job. Going "mini-heavy" with a pistol doesn't work outside Normal and you'll probably be kicked for trying it.

Short Circuit: Though it consumes metal, it can save your Sentry from rocket fire or grenades; the two biggest threats to a Sentry. You won't be killing anything with it though, and definitely don't try using it when Scattergun Scouts, Flamethrower Pyros, or Minigun Heavies attack - it will do nothing. Useful if you expect a lot of enemy soldiers and demos.

Wrangler: People will expect you to be carrying this, and considering its usefulness for helping a Sentry gun deal with giant robots and survive dicey situations, it's not hard to see why. I personally don't play without it.

Of course, no engineer discussion is complete without talking about...

Stock Wrench: Very well-balanced, and kills spy robots in two whacks. You can do a lot worse. Its biggest strength is its random crits, which can one-shot a Spy robot.

Southern Hospitality: In MvM it's viable alternative. The bleed is useful for dealing with spies. The fire vulnerability can hurt, but you aren't likely to get hit by fire damage unless a Flare Pyro pegs you or you get overrun. Even then, Fire resistance is tied for cheapest resistance upgrade available. Just remember you can't random crit with it.

Jag: Great for constructing and repairing stuff. If you lose your Sentry a lot, carry this and the Frontier Justice, so you can at least make use of that tendecy and minimize the damage losing the Sentry causes. Just make sure you switch away from the Jag and to the FJ when Spies show up, because the Jag will NOT two-hit them.

Eureka Effect: Using this is trading a lot for something you can do with the two-way teleporters upgrade. The penalty to repair and upgrade speed drastically interferes with your ability to set up a chokepoint if you lack Upgrade canteens. If you use this, carry the Rescue Ranger so that you have a more effective means of repairing your structures.

Gunslinger: The Gunslinger's mainly useful in that it frees credits on Sentry upgrades for things like resistances and movement speed, which are primarily useful to combat-Engineers. Only take the Gunslinger if you've got solid aim and dodging skills, and if you're confident you can make up with your shotgun what you lack in your Sentry. Treat the mini-Sentries as drop-and-forget. Blow them up and rebuild them instead of moving and repairing them. Blow them if you think they've done enough damage to attract Busters.

Now let's talk something unique to MvM, that is to say...

There are a lot of upgrades, many of them shared between classes. Going into all of them would get tedious, and this guide's already a bit of a wall of text anyway, so I'll stick to the important parts.

Building Health: One of the most important upgrades for an Engineer. It's the difference between losing a building and not losing a building. If you aren't using the Gunslinger, make this an ASAP priority. Your buildings are no good to anyone if they're constantly getting wrecked. On higher-skilled teams, you may be able to cut back on this, and take it later.

Dispenser Range: It's worth repeating. What you can do for your team is more important than what you can do for yourself, and your Dispenser helps everyone. In particular, Heavies appreciate it if they can wander a bit further from the Dispenser without losing the constant ammo refill, and it helps keep your Dispenser safe from splash damage hitting other players, assuming they use it.

Sentry Firing Speed: The faster your Sentry shoots, the faster the robots die. Improving Sentry firing speed also improves firing speed using the Wrangler, making your Sentry even better for gunning down Giant Robots and Tanks. Take only one rank of this - due to current bugs, your DPS won't improve with ranks 2 or 3.

Metal Capacity: You want a rank or two of this ASAP, but maxing it can wait. Having 300-400 metal lets you quickly deploy multiple buildings, and means you don't have go grab an ammo pickup for metal so often. Another benefit - ammo pickups will restore more metal, since the metal they restore is based on your maximum.

Upgrade Canteen: Popping one of these instantly finishes constructing and upgrading, then fully repairs and reloads all buildings you have placed. You can instantly fortify a chokepoint just by dropping your buildings, and then popping an Upgrade canteen.

Crit Canteen: Your Sentry cannot score criticals, but using a Crit Canteen will drastically boost its fire rate for the duration. Upgrade Canteens are generally a better choice, but these do have a benefit for Engineers.

Attack Speed (Wrench): The faster your wrench swings, the quicker you can rebuild or repair your buildings. Great for fixing your buildings under fire. It also make it easier to thrash spies.

Disposable Mini-Sentry: This gives you an extra Mini-Sentry, like the ones produced by the Gunslinger. Construct it the same way you produce your main Sentry - it'll be available once your main Sentry is in place. I consider it a very low-priority upgrade, as you can't repair or reload it, and it blows up once it's empty. However, it does contribute revenge crits to the Frontier Justice when destroyed, and Sentry Busters ignore its existence - it cannot provoke Buster attacks.

So you're not an Engineer, but like the benefits an Engineer brings to a group? Make life easier on 'em. Here's how:






Your Engineer has a lot on his plate. He's got a Dispenser and a Sentry to keep maintained, he's gotta make sure his Teleporters are in good spots, and he has to keep his own self alive as well. Don't take him for granted. If you're a Heavy, and using his Dispenser for ammo, and he has Dispenser Range upgraded, feel free to wander a little further ahead of the Dispenser, closer to the robots. It'll make sure they shoot at you instead of the building. In particular, if you're a Pyro, focus on killing, delaying, or relocating problematic robots that could harass the Engineer or his structures and make his life miserable, and never forget to spy-check. Use your airblast to reflect rockets and grenades being fired at the Sentry or delay Sentry Busters so that the other teammates can destroy it. If you have the Homewrecker, Maul, or Neon Annihilator, take a moment to whack sappers off an Engie's buildings if he's not around to do it himself.

You should also...

Most Engineers will set up next to an ammo pickup. They expect that ammo pickup to be there to refill their metal when they need it. If you grab it constantly, they're not going to have the metal they need to keep their Sentry repaired and firing, and that's gonna hurt the team. For Scouts and Pyros especially, consider using the Dispenser for ammo or roaming a bit further for ammo pickups if you need one. Beggar's Bazooka Soldiers can still use the Dispenser if they switch away from the BB long enough for the Dispenser to refill them.

The Engineer is not a one-man army, despite the fact that he's basically three weapons and a support at once. He can do a lot, but not everything. Don't lay the blame for a defeat solely at the feet of the Engineer unless he's clearly doing dumb stuff, like leaving his Sentry at spawn or placing it where it won't shoot at the robots, or hogging his Dispenser.

On that note, in order to avoid that...

If there's somewhere in particular you'd like the Dispenser, let the Engineer know. A good Engie will work with you. Don't make it a demand, and don't be a jerk and spam X-5 (Dispenser here). Consider asking politely over voice chat or text chat instead. A lot of Engineers will go to great lengths to help out someone who shows them a little common courtesy. Taking a moment to Z-2 (Thanks) after the Engineer has moved the building helps.

Sometimes Engineers are new to a map and don't know where a good Sentry setup spot is. If you do, offer it to him as a suggestion. Hopefully, your Engineer is not too proud to take advice, especially if it's good advice.

Speaking of pride...

Your Engineer is not some servant out to babysit you. You might not see him all the time, but you'll definitely notice if he's not present. Don't treat him like he owes you something. On the other hand, he's not your master either - if your Engineer expects you to follow a specific battle plan of his devising and won't compromise or work with you, or if he hogs his Dispenser or sets up his Sentry at spawn, then give him three strikes. Be polite the first time, be firm the second time, votekick him on the third. Engineers, more than any other class save for Medics, need to be team players, otherwise, they're just hogging a slot that would be better spent on someone who is.

In the end, I hope this guide helps both Engineers and non-Engineers alike better understand how the Engineer plays in MvM, and improves teamwork where Engineers are involved. I will admit, I made this guide after playing Engineer on quite a few maps, being thanked for my team-oriented playstyle, and then wondering why so few other Engineers I've dealt with do the same.

If this guide ensures that even one fewer Heavy has to go without a Dispenser when an Engineer is present in the team, or stops just one Engineer from getting a knife in the back thanks to a Pyro properly spychecking, then I'll call it a success.

[R] mooffinman | λ² - For being the one who encouraged a lot of my friends, including me, to get into TF2.

[R] Sparkeelecaro - For helping me out a lot during my nascent time in TF2, introducing me to Mann vs. Machine, and teaching me a lot of the fundamentals of the game.

Team Rocket Industries - For being a great bunch of goofballs that I'm proud to call friends.

The Official Team Fortress Wiki - Most if not all of the images in this guide were taken or adapted from there. It also proved to be an invaluable resource for research in the creation of this guide.

Valve Corporation - For the creation of both TF2, which this guide is based upon, and Steam, where it's hosted.

Props to those who've spoken up in the comments with things I might not have considered, or who have helped me keep my facts straight: |τcн| Linefor (BR), Teabag Crew #346, anomynus, Ducktor Hey Ducktor, Commander Hanji Zoë, [ACB] Farenite, gc | m00

I can't promise I'll include everything mentioned in the comments, text limitations being what they are, but I'll try to make mention of anything I consider genuinely useful.

Thanks to all those who've read this guide in its entirety, and taken the time to rate up, comment, or favorite it. I realize it's wordy, but I still hope it's proven helpful to you.