Dim Spirits: In-Blood - Complete Edition

There's a really odd skip you can do where if you let the flying ? block push you off the slope you could seem inly stand on nothing, hit the block to get the mushroom, then damage boost your way to the next part. I'm assuming this is a skip because it renders the buzzy beetle useless. There is also a skip in the third level with the shell you are supposed to use in the tight corridor in order to not get squashed by the ceiling. First take the shell, you have enough time to land on the platform before the munchers overtake it, pass the corridor, and then shell jump your way to the exit.