The part about buying the hammer or the scissors isn’t technically a bug... it’s just that the game expects you to progressively buy the weapons. It doesn’t expect you to, for no reason, save up money to skip the weapons. The hammer is kind of like a game state, it’s a trigger for a game event, and when you buy it, you trigger that event. Same thing with the scissors.
The issue with "he could run from me" or self-defense is more of a narrative break.