The treadmill bug isn't exactly a bug, It's just that at the end, your character is no longer crouching but in a falling state. And if a cannonball happens to be above you it results in you dying.
EDIT:Humor and mechanics were definitely on point otherwise. I enjoyed so much of this game, the art the music and the way you have to think about your approach because you can only move left. It's an amazing piece of work.