This game is relatively straightforward, but having a No Super Punch category might be favorable, considering that it can one-shot or two-shot every boss in the game excluding the final boss.

And also considering there's some pretty cool kills you can get on bosses using the powerup weapons, mainly the boomerang on the Lobster boss, where you can time your boomerang to glide across the screen on top of the Lobster, allowing you to two-cycle him.

There could also be some cool challenge categories, like Pacifist, or No Hit. If you're interested in running any of these categories, or you have a solid category idea of your own, let me know! (Although I discourage meme categories.)