Aesthetically, I love this game. Mechanically, I'm torn. Shooting is great fun and clearing a wave is satisfying, but the ammo scarcity keeps getting in the way of that. It can be difficult to keep tabs on ammo counts for each weapon, and I often found myself pulling out a gun I didn't have ammo for. A few of the ammo pickups are a bit hard to see, especially at a distance, which aggravates the problem. My other major sticking point are the flies. Its very jarring whenever they hit you, especially if they come at you from behind or above. I think I'd be preferable if they pushed you in a direction other than the one you were heading in, rather than stopping you outright. This way they'd still exert their disruptive role without overly intruding in the player's flow. But that's just me.
Regardless, I'm very interested in seeing how this turns out.