While most of the level was cool, there are some questionable design choices at some parts that I would address. Mainly just these three parts:

1. The usage of the flamethrower in the final section behind the Dweller wall is a bit much. There's no way for the player to see it and time their jumps, and if you've already committed to the jump, there isn't much to do but eat potentially two hits.

2. I would adjust the location of the walls relative to the hookshot points. There were many instances where Hat Kid clipped upwards either into or on top of the walls because initiating a hookshot cancels the Dweller's Mask while she's in the walls, which cause the game to freak out a bit.

3. As queso3d said in the comments, the ending was pretty rough. There was no clear indication on what I was supposed to do, and because there's no light in the final area, I wasn't able to see where the hole was and be ready to jump for the Time Piece. Placing a Twilight Bell at that section and maybe adding in a light point would be greatly appreciated and would go a long way in making the level more fun to play.

All in all though, it was a fun level! I encourage you to keep making stuff. :)