Alienswarm, Valve’s freeware co-op shooter is a must-have for fans of “crazy” shooter games like Serious Sam. This is a Windows 7 theme with 4 different wallpapers of the loading screen of Alienswarm.
Alienswarm is a remake of the original UT2004 mod. The team behind Alienswarm was hired by Valve to finish the game, so that they could release the game via Steam back in June 2010. As the name implies, you and your teammates are confronted with swarms of aliens, but of course you have loads of weapons to defend yourself.
If you haven’t seen it in action yet, here’s a trailer: