I'm really addict to this kind of game. I can shoot by my pistol, rifle and M16! The sound of bang! bang! bang! really make my room like a war!!! Even the games was so simple but I'm pretty damn sure you'll like it.
Select your weapon by pressing 1-3, shoot at the people going accross your screen. The more people you get, the more time you have to enjoy yourself! Full link here.