This is fun to play as it is now, and it could potentially have much more content! Have you thought about having enemies drop stuff?
We did consider enemy loot, but decided not to include it for the jam. Reason being, the main drive of the game was intended to be going deeper down, not farming enemies. That being said, I do think there should be a reward for getting through a big mob.
If anything, I would probably have the enemy spawners drop items because there are a finite number per level. If I had thought of that before the jam ended, I think it would have made it into the game.
Thanks for playing!