Thanks for the reply!
The vending machine just kept trying to attack me while I was in the boy's bathroom.
I waited for a pretty long time but it never left. I eventually got out but I got instantly killed.
I would say that, without a doubt, that is the most annoying aspect of the game.
The other problem is that I don't understand neither the chess puzzle nor the piano puzzle.
I did finish them, but only by pressing buttons randomly like a crazy old man.
I am not saying that the game is bad, but it just feels incomplete.