Thank you for playing the demo and WOAH, what a great review. Some of the bugs you have listed are known, but others I had not encountered yet. Thank you for all the details.
Funny thing about the pop sound for the player... it was a party balloon popping that I recored and edited in post. I agree that it can be bigger and louder. Sound design is something I am continuing to tweak. I also would like to do something so the cat pops are not so easily missed, but with later levels being much larger I have not worked out how yet. Maybe a Pop-cam? It shows up on the edges of the HUD and shows each cat pop? I do, also agree the the levels are simple in design. I wanted a difficulty curve that was not too steep but maybe I didn't go steep enough. Something I will consider as I move forward.
The idea about scraps left behind I really like, I am going to figure out how to add this.