Okay so you've told me the solution to level 2, but I didn't go further than level... 5 I think ? Where you have to wall jump. Here's why : the level is pretty hard and unforgiving, it seems you need to perfectly jump at the right distance so that you don't lose too much blood and then you can create a platform to reach the end. The watching eye is in my opinion not necessary and simply adds a challenge that does not belong in a level where you want to : first, teach the wall jumping mechanic, second, validate the platform creation system. The reason I quit is, when I finally reached the end, there was a bug I guess but I could not end the level. So I threw myself out of the level because I realized you would die by falling, but here I didn't so I just kept falling forever. Those are bugs I guess, but I did not want to play again because the game is pretty hard.
Or that's not that the game is hard, it's more the difficulty curve that is very badly dosed. As you said when explaining me the level 2, you've already been told that you need to teach a mechanic, then apply it to make sure the player fully masters it, so I won't say it again.
The controls are also too slippery for me. I think the reason I could not achieve level 2 is that it didn't cross my mind I needed more speed, since I am already really fast and I already can jump pretty far. So maybe slow down a bit the player because it's so hard to get used to. Another thing I did not like is to create platforms then fall under it. I feel like, when creating a platform mid air, you create it under your feet so you can just land on it (and that's what I thought I needed to do in level 2). It's not normal to jump, create a platform, fall, then jump on the platform you just created.
It seemed I could somehow get my normal size back, by maybe running into my blood or something, and I did not understand how I did that. Overall I think the games lacks explanations and feedbacks, it does not bother having to find out something by myself but here you have to guess almost everything. So yeah, fully explain your mechanics, and then create puzzles where the player is like "I know all the mechanics but I have no clue about how to do that ?".
And to talk about some details, remove the camera animation when you try a level again, or show it every 5-6 tries, because your game is a kind if die and retry, and so waiting a bit, even 2 or 3 seconds, is too much and quickly becomes boring. Also you have to wait for a few seconds before dying of falling (and you can see the skybox).
I know this comment might be hard but, keep in mind it's only so that you can improve your game and that it is also my personal opinion, you might not agree with me, and then I'll invite you to tell me what you think ! :) I liked the art, sound, and the game idea is really cool and fits the theme, so I'll be happy to play again if you update it ! Good luck and good job !