Visually, the game has some strange resolutions. For instance the main menu and UI text is super vague and pixelated compared to the actual player and obstacles / platforms. Perhaps you can adjust some settings on your images in Godot (I have only ever used Unity). The gameplay is really smooth tho, and the levels are quite creative! For the specific level with the 'fake platforms', with the walls closing in fast this particular level is more trial-and-error and hope for the best, which is a bit out of touch for the platformer concept it has.
The UI for the fps should also not be parented to your game-object as it currently flies above the screen if your player jumps. While playing I loved the music because I was thinking that you recorded yourself playing the piano, but you credited the sounds from some other place. The concept fits the theme quite well, and great use of the limited shapes.
Finally, your game icon on itch is probably the most appealing of the bunch! great job on that, really grabs the itch.io scroller to play your game.