Namco Bandai put a massive God Eater Burst demo online. How massive? The official God Eater blog says its basically the opening of the PSP game.
There are 29 missions to conquer plus story scenes to see in the God Eater Burst demo. Three advanced missions pit players and a computer controlled NPC against multiple Aragami. You can play the demo with friends over an ad-hoc connection, but the demo is not compatible with the retail game.
Data from the demo can be transferred into God Eater Burst. Players can either start the game over with the equipment you found or pick up from the point where the demo ends.