It was nice to be able to kite and kill huge heaps of enemies.. especially when using the decoy. The lore about cracks and monsters coming out of them was pretty cool too though abyssal ooze might've worked better than lava for theme adherence. One issue I had was that the enemies don't seem to spawn as per requirement. I was waiting for the last ranged enemy I needed to kill but the timer ran out. Perhaps you'd like to remove the timer instead?

Anyways, nice submission!