good stuff.. but dull
stuff should be cheaper, it's aaages before you can get the good stuff. and i didn't really find anything worth using apart from the rifle, so i was stuck with that the whole way through. things should also move along a bit quicker - much of the time is spent waiting for zombies to turn up. also, you should either fix the fact that you can't reload half clips, or change the reloading system - it's a nice idea, but i often found myself wasting half a clip because i accidentally left my mouse hanging over the guy.. also needs more variety, either in the form of more power ups, maybe traps for your base, and maybe more baddies.
for those who can't kill spiders, one shot from the flame thrower does it fairly quickly, but you might still want to keep em stunned til it does