Later today, there will be a big update with lots of changes and new content. The update will launch at 17:00 UTC.

More info here

Mod of the year awards event have started on moddb. Vote for your favorite mod and win games!

You can sign into moddb with your Steam, Google, Facebook etc account.
http://www.moddb.com/games/alien-swarm/mods
http://www.moddb.com/groups/2017-mod-of-the-year-awards

When you vote you get a chance to win a game from the #modlove collection.

http://gtm.you1.cn/storesteam/app/563560/

Prepare your guns, marines. Alien Swarm: Reactive Drop is come out!
To check how much time is left: https://reactive-drop-stats.appspot.com/

http://gtm.you1.cn/sharedfiles/filedetails/?id=807585816
http://www.moddb.com/games/alien-swarm/addons/forbidden-outpost
http://gamebanana.com/maps/193151

-minor balance changes
-minor visual changes (fog changes, less annoying special water, more accurate alpha on some diplacements, bad lighting one some model, etc)
-some perfomance optimisations and glitch fixes (ai pathfinding, bad collisions, vscripts api fountains precache and more)
-other minor stuff

Full source for developers included.

Yeah Fresh New and Next Level Alien Swarm map
http://gtm.you1.cn/sharedfiles/filedetails/?id=807585816
So prepare to reach the Forbidden Outpost!

http://www.moddb.com/games/alien-swarm/addons/forbidden-outpost
http://gamebanana.com/maps/193151
Full source for developers included.