I played easy and got to level 5 with about 120-130 kills. The heating mechanism works, well, but not well enough for a lazy camper like me who leaves clicking to the last minute.
Epic music and gameplay. I was seeing new enemies until my demise. Reminded me of the game I spent much longer on in last week's jam.
If I had one criticism, it would be in letting the mouse go outside of the play area. I wasn't too interested in watching sticks rub, and I guess I was missing there. OTOH it save me RSI slinging my mouse across the desk.