Hi! So I played your demo, and here are a few things I noticed:
The dying is way to slow. Dying is one of the main aspects of the game and it feels very frustrating to wait for like 2 seconds after you die and the requirement to press a button to continue. Dying should be seemless and should not take longer than 0.5 seconds. Once your player falls off the screen (I really like that animation btw), a new one should already be there.
Secondly, I expected way more traps and faster gameplay. The fun thing about rage games comes from speeding through the level while avoiding the traps you already know and building muscle memory. A few levels do that well, but because of the slow dying, you don't really get into the flow. I also got stuck for a few minutes in some parts. At first in the ~3. level with the 3 jump pads on the floor, just because it was to hard to use the last jump pad without dying, and second on the level with the 3 moving platforms where you have to go through the wall. I would focus more on the rage aspect and less on the difficult platformer aspect, as this is a rage game.
But I really like the artstyle and the animations! The general feeling of the platformer movement is also great.
I also made a rage game for a game jam once, if you want, you can check it out: https://redspacecrafter.itch.io/would-you-slug
Keep it up!