Idk what version of Godot you're using, but please use the AudioStreamRandomizer resource for things like item pickup sound effects. Just pitch shifting randomly on playback will make the sfx much less grating. You can also use it elsewhere for other really repetitive sound effects for the same benefit.
Controls nicely, but there is nothing overwhelmingly standout at this stage, I think one of the next things you need to do is give the game a more concrete identity outside of its platformer mechanics. Some game "juice" would be also pretty positive to work in at this stage, especially given the games more stylized nature. Stuff like pushing walls when you try to walk into them, ledge teetering, etc. Some simple particle effects (like dust while running, poofs in the air when air dashing, etc) would help contribute to good game feel, while being easy to swap out later.