I'm the worst house sitter.
I played the optimized version. Unfortunately the letter disappeared very quickly so I didn't get a chance to read what to do.
So instead I tried to imprison the monster in a mountain of furniture and food. Clearly it has been hitting the gym because it broke through my barrier every time.
Despite not playing the game as intended, I can say I like the art style. It's a bit strange how slow the objects fall though. If you upload another build I'll try play the game according to the instructions!
Sorry for imprisoning your monster :(