Like the other gran turismo's before it, Prologue is about 1/4th of the actual Gran Turismo 5. It has something like 40ish cars, 16 tracks? Essentially, like captainfrizo said, it is an extended demo. However, it has 16 player online, and runs at 1080p at 60fps. it's a decent price and is better than most racers out there already, but i think i'm just going to wait a few months and get the full gran turismo 5.