Thank you for playing! I’ve heard about this bug once before and haven’t quite figure out what the reason is. This enemy is meant to go round and round, but I admit, the code for it is a bit (very) junky, so anything can happen. My guess is that it gets slightly misaligned when colliding with a checkpoint and switches to going upwards while still being against the wall.
Glad you had fun! :) This game is the first in my “games to finish someday” list, so I’ll definitely get back to it. Eventually.