Although short the Mirrors Edge leaves you wanting more. The combat and some of the more specific moves can be a bit hard to master, you can see that there's a ton of room for the game to let you move around a bit. I think 10-20 years from now Mirrors Edge will be referred to as a Concept Game for First Person Shooters, sort of like Dark Side of The Moon for Rock, in line with Portal and Doom. The basic idea is that you can jump from rooftop to rooftop, trying to escape police in a big brother dystopia. The game has a sort of Matrix feel to it. Think about it, your trying to escape police by jumping long distances in a dystopian world, disarming enemies with martial arts-like moves, with gun play, in a city, and heck there's even "bullet-time". If you were a fan of the matrix you will like this game. Hell I wouldn't mind if this game were called the Matrix.
Anyway like I said at the start I can't really get into the plot because the demo was pretty short and also like I said it left me wanting more. Eventually I will buy this game (After Fable 2, Fallout 3, Rock Band 2 and Gears of War 2), or at least rent it.