Bots Acclaim is a cool game where you pick between a robot with wheels/tread, hovering bottom or legs, then battle enemys with others online! You can level up, make friends and equip new armours like helmets, shoulders, guns, sheilds and alot more!
http://bots.acclaim.com/ to find out more, I have played this game for almost 4 years and I am the highest level you can get in the game, 100.