Overall a fun game! I enjoyed the art style and the comedy element to it all. The idea of some pour soul armed with only a spray bottle and a broom pushing monsters back into a pit is really funny. The gameplay itself is nice, everything feels good and the fire scene transition is a super nice touch.
If you wanted to improve, I suggest adding background music and some sort of score functionality where the quicker you get monsters back into the pit, the higher the score you get it. It could work like Mario where enough score gets you health back or you could have a shop system for additional items / upgrades.
Overall this is a super fun game with tons of potential! Nice work!