Nice little game! Controls feel nice (maybe a bit too responsive, but only my preference, I mean a really quick tap on the arrow key causes a big dislocation), and the level layout was nice. Furthermore, I appreciated you did your own art/music! The game runs smoothly!
One super small observation. The Z-Index (I used Godot too, nice!) of the UI element relative to the barriers in some areas of the game: the white outline of barriers is rendered over the black outline of the health bar and something similar happens with the gems counter (my I would put UI element in a separate CanvasLayer with higher layer number)
Nice job, keep up the good work!