Some enemies have the headless chicken effect. It's actually a feature lol. One version had them die instantly but it made the game really a lot easier actually.
I feel bad for ruining your good run! D: the bug near the tower of endless is a new bug that came with the latest version apparently. It's a bit mysterious to me to be honest. Have you tried it again on a seperate run? I'm just curious if it happen every time you go there.