Ah, I love this game.
For a free online game its got excellent graphics and game play.
They've recently added and awesome co-op mode, and they constantly add new maps, guns, and game modes every month. Every time you play in a round you'll have a different experience. There are many guns at your disposal, which you can upgrade with silencers, scopes, and extended magazines. Even with the pistols you can attach a scope (which is fun in the pistol only games

). There are no vehicles, it's all infantry based battles. This game is incredibly addicting. In fact, it is the best first person shooter for the computer I've ever played. I own games like Battlefield 1942, Vietnam, and Korea, and Combat Arms
surpasses all those games with its graphics, choice of weapons, and overall fun. I hope you enjoy it, have a great time playing!