I like the idea !
You can improve the movement of the player by add a longest curve of speed progression. It will increase precision on those tiny little pentagon platforms. Maybe you can be interested by this tutorial https://kidscancode.org/godot_recipes/4.x/2d/platform_character/index.html
Thanks to use physical key, I am on an azerty keyboard !
The idea of panel moving for the menu is interesting (Maybe you can move them a little bit faster). Also, maybe you can be interested by this project I participated to develop https://github.com/rakugoteam/Rakugo-Game-Template . It handle GUI scaling when you have tiny or big resolution.