The procedural generation aspect is neat, but if it wasn't mentioned, I wouldn't have known it was happening (until I played a 2nd time). For long load times, having a progress indicator would be helpful to indicate why the wait is occurring. The art itself looked nice and had a good theme.
Gameplaywise, having enemies move a bit faster, but also die faster might keep it a bit more engaging. I might just be a fast clicker, but I was often waiting for enemies to appear. I also found you could run into enemies to kill them at the cost of 5 ammo (but none regained after), which might be worth mentioning in the game description if it is intentional. I also found that my ammo could get into the negatives, so I wasn't actually limited by it. Might be an opportunity to consider a future mechanic for the situation when the player runs out of ammo, but is still alive.