Hahahaha, I clicked on the quit game button. Well done. I find it funny that so many people put the quit button in their webgl builds and it was fun to see someone use that.
Great job on this. I really appreciated a lot of the choices you made here. Leaning into the absurdity and making the zombies squares really made me smile though. With the exception of the few bugs you mentioned in the description, everything felt pretty good.
I might consider decreasing the respawn time a bit. If you have to be replaying a level several times to complete it, faster respawns would help keep the momentum of gameplay going. It can feel a little slow and sloggy otherwise. Also, maybe increase the weight on the dead zombies a bit? I had a few weird moments where I would jump onto a platform and knock away the body already on the switch. Particularly in the sawblade levels, I ended up dying more than needed trying to put those bodies back. Little things though.
Overall, congrats and well done!