[Spoiler for an end-game unlock]
This was great fun! Nice levels, great music, good art and nice controls.
The charge jump mechanic was a cool idea, and you managed to do a good job of implementing it. Took me a bit to get used to since I'm used to jumping immediately when I press the space-bar, but after a little while I had it down.
If you end up working on the project more in the future, it might be an interesting idea to add some alternate paths for players revisiting old levels. I didn't notice any possible alternate routes on my first play-through, but having levels that are designed with more abilities in-mind would add a lot for replayability. Especially if you tracked time too.
Probably my favorite thing is the wall-jump and its animation (I probably spent a good minute just looking at the pretty animation). It opens up more possibilities for level design and felt really satisfying to use. Kind of like the Celeste boost-jump.
Congratulations on your first game jam! Great job :D