I like the art style, and I think Godot is a good choice for this type of game. Some good music (even royalty free stuff) would go a long way in this. I'm thinking some 80's rock or grunge or something.
Ok, a few big issues with this though.
When going to the side I seem to be gaining speed even when bumping against a wall, thus holding right and then jumping makes me bounce off the wall to the left. This is infuriating when I am trying to jump up to the right. In fact, the whole player control system should probably be re-done to feel more responsive.
although I like the idea of building up momentum, and I think that would be really good in a platformer (almost like Sonic)
I see that this is your first game (on itch atleast) So I like to send this link to anyone new and wanting to make platformers. It is way too detailed, but it shows some things to think about with a player controller: