Brains! Brains!
Worst voice acting ever, but quite possibly the funnist game I've ever played. The first zombies sound like McDonalds workers on crack, the rest are various degrees of the word "brains" and/or "hungry", or just plain "urrrrrggg". Classic!
Also, bonus for the "Bed 'o Nails", though maybe Caltrops would be more effective? Landmines are cool, I love how they catch fire. (the zombies, that is).
Weapons are the classics with some fun, they include a BBgun, Colt 45, shotgun, sniper rifle and a non-automatic Uzi SMG, plus grenades. I would have liked to see a rocket launcher, a big machine gun, and/or a laser or something suitablily insane. I think you took this game too seriously in everything up to the voice acting.
Some suggestions:
-Make some levels with HUGE waves of zombies. To make these parts non-laggy make a special zombie for it with simple shapes and flat colours, then multiply them. You know, grenade/machine gun fodder.
-Include above suggested weapons, and make the Uzi Autofire.
-BIG zombies, or zombies driving tanks/cars at very slow speeds.
-More areas to more around in the house. A bigger firing platform. Maybe you could upgrade it with mounted machine guns and stuff.
-A level 1 defense could be little brass tacks.
-Death traps, like holes with spikes.
-Exploding zombies, when attacked with explosives, have them fly through the air.
-A "zoom" for the sniper, if this is included than add an AUG, too, for sheer awsomeness.
I suggest alot, eh? Well it was a great game, and could have a killer follow-up. Now, I'm off to fight another huge blanket of the living-impared!