Steel Storm: Burning Retribution

Steel Storm: Burning Retribution is a top-down 3D Shooter (a chasecam view is unlockable) in which you control a hovertank to fight off extraterrestrial invaders with a good number of weapons. You have to succeed in various missions on many different maps by fighting any enemies you might encounter on the way, opening gates, collecting weapons, extras and points and blowing stuff up. The enemies include various sorts of defense towers and hovertanks.

Of course you can play multiplayer games in cooperative mode or deathmatch and capture the flag mode. There even is an editor integrated, which lets you create missions, campaigns and multiplayer settings. These missions can be shared with other players.