Good concept and insane art !
I died a lot in that acid, so the game clearly leaves an emotional mark (and a physical one for that poor cat), and also a lot due to the flying enemies. So maybe would be nice to add checkpoints or to ease a bit these bombers (I think they are a bit broken to, if you shoot them a bit early, the bomb is not destroyed but it drops a second one immediatly).
For the boss, the battle wasn't long but a bit repetitive, as I was just camping on the left till it died. Yet the boss, as the rest of the game, is gorgeous pixelart and the gameplay is very clean.
The twist is fun, and the whole game is so polished, it's amazing.
PS : my brother is attempting no hit runs, that's not much of a success for now XD