 "Mirror's Edge" has a distinct visual style, with the outdoor environments predominantly featuring white and distinctively lacking in green (for example, trees and foliage would appear completely white instead of in their natural colours), punctuated by deliberate use of strong primary colours.According to Senior Producer Owen O'Brien, the stylistic choice allows the player to focus on the Runner Vision guidance, as well as serving as a health meter; the colours become less saturated as Faith starts to take damage.Because development of "Mirror's Edge" began before DICE's own Frostbite was completed, the game uses Epic's Unreal Engine 3.