Dayum nice game
The controls are pretty easy to pick up and the gameplay, though simple, is addictive. It gets pretty hectic, even with the broad selection of weapons and grenades/ etc, and tests your shooting skills pretty well. The audio is great - different gunshot noises and screaming/groaning are well done. The graphics are pretty simple but not in such a bad way (its quite charming, seeing these little figures kill each other :P)
Overall, I think its a great game, not perfect, but very good.