This game only has one enemy, and it’s an arsonist he is a boss character and you’re supposed to fight it using all of the puzzle mechanics you’ve learned like a final level, it’ll have to be interesting enough, either there is this kind of enemy or this game shouldn’t have an enemy or antagonist.

It would be fun to have to throw him out of the window in the last level, you could follow him while he puts you in troublesome situations and when you catch him you throw him out of the window and the authorities arrest him.

A mechanic that could help bring more of that is Evidences, evidences help you identify the arsonist but it may stray further from the experience intended.