For these achievements, just play the game. By the end, you'll have all of these regardless of what you do.

Chapter 1 - The quest for the Silver Fosfos

Finish chapter one.

Chapter 2 - The Secret Place in the Root Forest

Finish chapter two.

Chapter 3 - The Abandoned Dynasty

Finish chapter three. -- This Achievement is broken for some people, as evidenced by this achievement being unlocked less than either the Chapter 4 or Chapter 5 achievements. Here is a thread with a possible workaround and a save file to help. http://gtm.you1.cn/app/251430/discussions/0/630800444916636469/

Chapter 4 - The Secret of the Basylians

Finish chapter four.

Chapter 5 - Asposia's Last Hope

Finish chapter five.

Pigeon-Tunnel

Try to capture the pigeon without using the string on the windsock.


Schnapps-Dealer

One the very first screen where you get control of your character, take the bottle from the ground and immediately try to give it to the garbage dealer.


Fresh Breath

In Chapter I, eat one of the mints from the Sin-o-Mat.
This achievement was fixed in the 1.5MB patch released on Steam on Oct 7th, 2013, and I can confirm it now works. I do not know if the patch was released on GoG.

King of Sins

You just need to talk to Ottilie in the bar about both of her sins in chapter one. Achievement fixed on Nov 22nd, 2013.

Trial and Error

This deals with the Mechatre Puzzle (the stage where you can use levels to change what appears). I'm not 100% what triggers it, but I didn't look at the script or open the door (so I didn't see the images there). I then completely the puzzle. That didn't trigger it though. I then moved between the options for the people and it triggered while randomly moving levers. Achievement fixed on Nov 22nd, 2013.

Windfall

Once you have the fruit down from the tree, try to use it on the traps before punching holes in it with Gorf's claws. You will drop it on the ground and get the achievement.

Brainteaser

Put on the helmet and use the tree to have a fruit drop on your head. Be sure to do this before you put the tunnel mouse on the helmet.

Gorf-Scratcher

Once you have the hook, talk to Gorf until he mentions a dry spot on his head. It should now appear as a hotspot on his head (if not, keep talking to him). Once it appears, use the hook on his dry spot.

Master of Stirring

Once you are controlling Laura, go talk to Gorf. Once he mentions the glasses, a hotspot will appear on the swamp on the right back portion of that area (not the one directly behind Gorf). Get a reed right beside the new hotspot and use it on the swamp.


Suicide

Once you have the glasses, to up the treehouse and attempt to use them on the Wind Monk. Be sure to do this before you use them to get the screaming ant, because Laura will not pick them back up.

Casanova Casonostri

Once you have the flowers from the courtyard, attempt to give them to Gorfelina.



The Royal Toilet
In case you just want a hint to this one, ignore the text on the achievement and look at the image for it instead. Brown tickets are what you are after.

Ok, the solution. You know how you normally make the golden tickets? (and if not, why are you here?). Do that, except DON'T put up the gold rug. Without the rug hanging on the branch, the tickets will turn brown instead. Take your new brown tickets and give them to Steve for the achievement.

Hedgehog- Anesthesia

Put the knock out drops on the Conroy puppet. Give the Conroy puppet to Fonk.



Chief of BBQ

Once you have found Laura's father, but before knocking out the guy downstairs through the grate, talk to Laura's father a couple of times. He will be shocked each time. I believe you only have to talk to him twice to get the achievement (not counting the time he is automatically shocked when you first enter the room).

Just a scratch

You know how you defeat Conroy in the last puzzle in the game? No? Well, you should figure that first out because this will spoil that puzzle for you.

Anyway, now that you're back... Just do the same thing but use the de-petrifying eyes instead.

Casual-Gamer

Just use the help system until you get it. Shouldn't take long.


Mr Wise-Guy

Don't use the help system at all. I do not believe just opening the help screen counts. Just don't actually click to get any hints. You are allowed to use the space bar to see hotspots.

This achievement was fixed in the 1.5MB patch released on Steam on Oct 7th, 2013, and I can confirm it now works. You can use an old save game from before the patch to get the achievement. I do not know if the patch was released on GoG.


Blabbermouth

Talk to everyone in the game.
This achievement was fixed in the 1.5MB patch released on Steam on Oct 7th, 2013, and I can confirm it now works. You can use an old save game from before the patch to get the achievement. I do not know if the patch was released on GoG.