I recently discovered a very interesting glitch that completely breaks this game. If you die while getting damage boosted into a life potion -- therefore dying with HP -- the game thinks you completed the current stage and will advance you to the next stage. This works in every stage with a life potion, including all the boss levels and the final boss. This glitch works in both the SMS and GG versions of the game.

I haven't done any runs yet, but this would result in an enormous time save and make the current WR time completely uncompetitive. I'm thinking we'll need any% and glitchess% categories for both the SMS and GG boards if anyone submits any runs with this glitch.

Here are videos showing the glitch in action.

SMS:

GG:

Awesome find. I've been messing around with this in a TAS setting and have been able to skip every level apart from the round 2 levels (I suspect 2-3 is possible but yet to confirm). I thought 2-1 might have been possible but I can't grab the potion when dying since you need to duck to get it inside the wall.