IT's a nice idea that I think would work great with some upgrades as you progress. It was tough moving with mouse and camera with WASD!
With the inaccuracy of the horde, it felt tough to avoid bullets, though at around 3k points there was way too many to avoid regardless.
A decent foundation if you wanted to take it further. Oh, don't use the same noise for eating a human and losing a zombie as i thought i converted someone but he'd actually just shot my zombie.