It is a completely different ball game from UT2K4, or, to be honest, anything I've played in memory. The emphasis in UC2 is more on the array of characters (Fast and weak to slow and tough), melee weaponry being just as useful as gunplay (Though that depends on your character's size), and lots of wild wall-jumping acrobatics. Adrenalin moves also make each character unique, et al. The entire thing bears little resemblence to UT2K4 (Except in guns and a few characters), but is itself an excellent game.