Great game!
I think the art style is a bit repetitive at times, but this is fine for a game jam project (Can't say that my project looks all that great either :D ). The levels themselves though play great and as someone else mentioned here, the difficulty curve is good. I also love the small detail at the beginning, where depending on if you jump or move first, the text changes to reflect that. That was a really nice detail!
And as another Godot user it's great to see games made with it, and also: In the export options, you can choose to embed the .pck file into the .exe. And then you end up with only one .exe instead of needing to zip up the project!