I personally think it was a pretty good game of course it could have been A LOT better but the source code and the sdk is what makes it really fun for me.
Other reasons:
1. Who doesnt love killing aliens?
2. Reason number 2.
3. It's FREEEEEE!!!!
4. I'm addicted to any game with a map editor.
"Alien Swarm"
Moderator: Gaming Addictees
Re: "Alien Swarm"
ammoman you should buy starcraft 2 it has a very extensive level editor thing. And my friend said he loved alien swarm