When Mirror's Edge works it's genuinely fun. Running and vaulting away from the police as shots ring all around you is genuinely exciting. Unfortunately, it's let down by its ambitious nature. Because it's in first-person, it's tricky to be precise at speed. When you're not sure of your exact footing it's easy to miss ledges and plummet to your doom over and over again. In fact it brought back memories of the original Tomb Raider which isn't a good thing.
Luckily, the checkpoints are close together so you're never thrown too far back into the level, except when you're doing some of the chase scenes. Mirror's Edge is an interesting idea but it doesn't quite hit the mark.