Lots of small audio bugs: music not restarting when unpausing or punch sounds disappearing after a while, desynched enemy attack sound when they're attacking the floor.
One time the game got stuck on level 4 and never went to level 5:
Got repeatedly filtered by wave 15.
The brick area you hit when punching from below doesn't seem to be consistent: sometimes you will jump at a crab and the blue bricks are much smaller and you'll nudge the crab forward instead of stunning it which is very annoying because that crab goes from ammo to problem. idk if it's supposed to be a mechanic and I didn't get it.
Rebindable keys would be great I usually play these kind of games moving with WASD and doing the rest with my right hand.
Sometimes enemies spawn from the side of the screen instead of doing the normal drop thing.
Sometimes hitting the enemies with an upward punch changes their direction. I think this is intended but occasionally it doesn't work, although it might be some wonky physics where the enemy is technically changing direction but is in mid-air except too close to the wall to fall until the knockback from the upward punch has ended.
I wish punching kept a smidge of momentum instead of stopping you completely.
Lots of fun overall.