Day and night!
Daytime? Nice, warm rays of orange sunshine as if you were perpetually awaking from a refreshing cat nap? Sure, whatever. Drop kick zombies freely, like you're Faith from Mirror's Edge. Even zombies look a bit silly and listless in the daytime.
But at night? That's when things get spooky. Checking out Dying Light at PAX, Hamza said the daytime portions felt quite similar to Dead Island. Not surprising -- they both come from Techland. Thanks to a day and nighty cycle, like in Pokemon Silver, the game can get dramatically more horrifying.
The idea of "Mirror's Edge x zombie game" entices me more than just about any thing someone could try and do with a zombie game -- and they sure as hell are trying them all. Mostly it's because you said, "Mirror's Edge." That's my weakness. Mirror's Edge x the Yalta Conference? Sign me up.
But, really, only killing your way through zombies, as we're wont to do in games, seems silly when we could turn tail and run. Having a better system of escape seems reasonable. Sometimes the best defense is not guns, but runs.