Being that I am new to the iPhone device, I was actually impressed with how good it looked. Each character model is rendered in 3-D and the art style is used wisely to cover up the shortcomings. The characters look better than something on the DS, but not quite as good as the PSP. The developers get away with making characters look great because the environment is entirely devoid of any sort of life. What is essentially a large square with grass and dirt and a picture of a city behind it, the "field" in which you kill legions of the undead, can be overlooked for not having any detail because honestly, you aren't focused on the ground while you play.
Actually, you aren't focused on anything but the unending moans of the flesh-eaters that slowly make their way to your fort. The Menu screen has some ambient B-movie horror music, but the field has no music at all. All that can be heard is the cacophony of weapons fire and zombie death. This is not a game to play in public with the sound on, because you will annoy anyone around you with the sound effects. I wouldn't even recommend headphones because there isn't anything relevant that is passed on through the audio, so feel free to keep this one on mute.