This feels like the ideal result from a Game Jam. A game which, even when compared to games without any restrictions, still holds its own as a concept and puzzle format.
Great mechanic, with compounding layers of difficulty naturally interwoven, just a joy to play. The art and music worked well too.
If you continued development, I think more clarity about how things work, and what is happening would be really welcome. Highlighting who you're controlling, showing what the win condition is for both monsters and humans at the same time, making it clear which monster is closest, and then some juice and that's a successful game in my opinion.