Dungeon Defenders is a competitive online game which blends Tower Defense, Gauntlet, and a bit of Dungeon Keeper. It looks like a lot of good, competitive fun.
Anyone who decides to pick the game up early on Steam will gain access to promotional items from Portal and Team Fortress 2. As opposed to TF2’s hats, these items have actual use in the game as weapons for Dungeon Defenders’ various classes.
The exclusive bonuses are:
The Aperture Science Handheld Portal Device for the Huntress hero class. Constantly consuming energy when active, this device allows it’s user to open portals from one location to another and can be used to greatly extend a trap’s range, quickly teleport across the map, or confound enemies!
Four Team Fortress 2 Familiars:

– The Heavy: Uses his Gatling gun to shoot at enemies from afar.

– The Engineer: Repairs groups of nearby towers while you’re on the offensive.

– The Medic: Heals a group of nearby allies amidst battle.

– The Pyro: Uses a flame-thrower to set your foes on fire.
Besides launching on Steam, Dungeon Defenders is also set for a release on Xbox Live on October 20. The game’s will also be released on PlayStation Network at a later date.