The best free game that I have ever invested almost 1000 hours of my time on! The concept of Zombie Panic! Source is to survive and do the objectives to win, or survive long enough to kill all the zombie lives, or until the round time is up. Once you get killed by a player zombie, you turn into a zombie and have to kill the humans. Before I started playing ZPS I wanted a game with this similar idea and was satisfied when I finally got to experience this game. Decent community, aside from the hackers, exploiters, campers, trolls.. That and the game needs an update because many players have quit playing as it is. ANYWAY, Overall, It's a pretty decent game, and if you haven't played this game, I suggest you give it a try. I'm sure everyone would enjoy it once they learned the basics of how to play.