There is a few glitches in punch quest, a couple of them are these:

CYCLOPS GHOST- Sometimes if you punch ( or just let it glow) a small skull that mega skull barfs out, you can see a faint glowing icon of the cyclops boss... That must be a glitch seeing that you would really only reverberate back and see a purple glow. (but it might not, it might mean something else...)

Cyclops ghost
you can just barely see it, just look closer.

STACKING SKELETONS- Once I was running along at the first stretch of dungeon and I saw 2 skeletons on top of each other- but that's not it. They had spears, but spear skeletons (other than the starting screen) do not spawn until level 4-5 or 5-6. This still remains a mystery to everyone, but it has a minuscule percent of happening.