It turns out there's actually a lot more to this Xbox 360 gore-fest than smashing as many zombies as you can in the face.
From GameInformer : "In previous coverage of Dead Rising, we talked about the overall gameplay structure and story elements (February, April). With this latest build we can now speak to the progression system, alternate unlockable game modes, the first boss fight, and how far the game is coming as a whole.
As you work your way through the game, you can earn prestige points by escorting survivors to safety, killing zombies, completing cases, and taking pictures. Every time you level up, photojournalist Frank West will gain either an attribute upgrade or one of approximately 45 different skill maneuvers (including a jump kick, shoulder climb, and various other wrestling style moves). Different attributes include attack power, speed, maximum health, item capacity, and throw distance.
The main story moves along by completing cases. In the past, Capcom has maintained that these were a completely optional part of the game. But now they have decided to require the player to complete case files in order to progress past predetermined points. "You cannot, as previously stated, sit in a closet for the whole 72 hours," Capcom said in a statement."