Fantastic, but still in need of work!
First off, the graphics are great, really great for the variety of zombies (By the way, awesome variety of zombies!), however, I almost had to stop using the chainsaw because of how much you'd stick on the wall.
Good job on the weapons and weapon system, although it more or less makes the previous weapons useless every new one found. In example, once you get the M1A4, any automatic before it is useless, once you get the Uzi the M1A4 is useless, once you the the AK-47, the Uzi's useless, and so on. It makes sense, but I'd like more variety in the weapons besides slight differences in damage, rate of fire, and ammo capacity. Either make more drastic changes to each guns individuals stat, or make original effects for each gun.
However, still great job on the weapons.
The one thing that really bothered me, and this is my only real complaint, is the weapon swapping system! Let's say I have a hunting rifle out, and a shotgun in secondary. I fire and and miss as a horde of zombies are about to reach my gate. Naturally, I'd want to change to my shot-gun and show them some lead-based love, but I have to wait the 2-3 seconds for the hunting rifle to reload before I can even swap, and then wait before it allows me to actually fire. Make it so you can swap weapons anytime during the reload, and if you do this to at any time other than maybe the very end of the animation, you have to restart the reload when you pull the first weapon out. Otherwise there is really no other point of using secondary weapons if you have a good enough primary.
Or, if you really want to be adventuress, make it so if you are using two one-handed weapons, by switching over to the secondary (after un-loading the first), the first would reload automatically (While using the second). Again, just a suggestion.
There's more stuff, but I'm rushed for time, so great game, is it too much to ask for a sequel?