Mirrors Edge is a very good game, it's completely different to anything you will have seen before. Download the demo and see for yourself, if you liked it, you will love the full game.
Although, yes, the story is quite short (Around 7-10 hours first playthrough) there is so much more to do! There are plenty of time trials with more maps on the way, addictive speedruns for each level and of course, finding the hidden bags. You will also find yourself going back through earlier levels looking for spots to get the achievements such as "May I have this dance?"
If you can complete it in one day, you must have no life. I'm sorry, but it's true. But if you play all day long it's not going to last, is it? It took me a week to complete the story but I am still playing it, and the replayibility is good.
My first playthrough was normal, second easy so I can go through all of it without using guns and then again on hard.
Some people have found the first person view annoying but saying you can't see your feet is completely wrong because, if you look down, you can. I personally don't have any problems with it, I think it makes the game much better and I don't have any difficulty with timing. Of course, it will take time at first but you will soon get into it.