Having just beaten the game last night (something I've never even APPROACHED doing on the PC or PS3 version), I will say that it is a few things.
1) It's damn short once you get into your running groove
2) The controls are MARVELOUSLY not complex at all, and easy to remember, even if you should somehow panic
3) The aesthetic of Mirror's Edge makes this probably one of the most visually unique iOS games out there
4) It's BETTER than the PC and Console versions
5) It's dirt cheap compared to the other versions
WHY THE HELL AREN'T YOU PLAYING THIS YET?
In case you're on the fence, here's a quick video walkthrough of one of the stages so you can see how simple the controls really are.
Mirror's Edge iPhone Chapter 3-1 Ambush Walkthrough With Hidden Bags