Alien Swarm Returns With Workshop Support

[Mr. Robot]

And the best part is that it (unofficially) works in Linux!

Use PlayonLinux's program to install Steam, then login and install Alien Swarm:Reactive Drop

Notable issues are that the windows don't scale well and the bottom of the screen can get chopped off
-to get around this play in Windowed (without border) in a smaller resolution than your computer screen.

Also there is no offline DM with AI bots (unless Onslaught is enabled, where you can fight aliens)