One of my all time faves!
I haven't played many good horror based games anywhere since well... not many can compare to what you have done, I love this game, tho a few little things could be done to make it more scary.
You could add some type of video of the survivors actually walking around on missions and showing them attacking and or being attacked by zombies, that and make it kinda show life going on within the compound, don't get me wrong imagination is good, tho I would love to see people living and or getting torn apart, maybe SickDeathFiend would come on board and do some video?
I would also like to see a alternative side, maybe one where you can also control the zombies or be something with zombies and attack survivors... I dunno, would be interesting to see how that could work, maybe you can make a mmo in the future?
Well keep up the great work, can't wait to see version 3. :D