A lot of people's main complaint with Mirror's Edge is the narrow field of view. It can cause motion sickness and in my opinion prevents the game from being as immersive as it could be. Fortunately it's pretty easy to modify...

First, go to:
C:\Users\YOURNAME\Documents\EA Games\Mirror's Edge\TdGame\Config

In there you will find a file called TdInput.ini.

Open it with Wordpad or your prefered text editor and paste in the following text with the other bindings...

Bindings=(Name="NumPadZero",Command="FOV 0",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadOne",Command="FOV 32",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadTwo",Command="FOV 75",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadThree",Command="FOV 80",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadFour",Command="FOV 85",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadFive",Command="FOV 90",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadSix",Command="FOV 95",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadSeven",Command="FOV 100",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadEight",Command="FOV 105",Control=False,Shift=False,Alt=False)
Bindings=(Name="NumPadNine",Command="FOV 110",Control=False,Shift=False,Alt=False)

Save the file and you're good to go!

Now make sure Num Lock is on and you can use the number keys to select different FOV values on the fly. You can change the values to your liking although I would recommend leaving the default FOV value (90) as an option because you'll find that sniper scopes will become inaccurate at other values and you may want to change back.

Enjoy!