While it's no id Software Rage or Counter-Strike: Source, the Steel Storm: Burning Retribution game was released yesterday.
Steel Storm is described by its developers as an "indie top-down archade shooter" with single-player, death-match, and co-op game modes. The game is being simultaneously released for Linux, Mac OS X, and Windows operating systems.
This game is described as fast-paced, streamlined, online warfare up to sixteen players, 25 different campaign missions, and new missions can also be created. Below is the trailer for this game.