I noticed that there seems to be a very tight (maybe frame perfect?) trick where if you hit the top of one of the crab shells just right, you are damage-boosted to the other side of the enemy. Has anyone figured out how to hit this consistently? I just hit it randomly on occasion while jumping over a crab.

Yes I've known about this for a while but it is not consistent. Getting it in a run messes up cycles later in the room so unless you're prepared for it to happen it ends up screwing you