I think you should add a little bit of "view" all the way around the character to add a scare factor when a zombie suddenly attacks from behind. Instead of you suddenly realizing your health is depleting and not seeing the zombie behind you, you would be able to see the zombie right on top of you at the very last second.
Also maybe you could not make the view so bright. It kinda seems like the guy has flashlights for eyes. Or you could make it so that your character could start off with only a flashlight and just make a gani with the guy holding the flashlight.