Excellent work.
It lagged on my piece of crap computer but that's my own fault. This is an amazing game. It flows seamlessly and it has some great and truly original elements to it. Like the search for survivors for example. The weapons are all fun and have their own distinct advantages and disadvantages. If this is your first game then I'm truly excited to see what you come up with in the future. You obviously thought this game out a lot and put a lot of effort into it, and that shows very nicely.
Almost perfect, what else can I say?