The issue that I had with the jump was that you could only move left or right BEFORE pressing space to jump. When moving in one direction, this isn't too bad as you're likely to be holding down the direction as you're running, then jumping. But on small platforms, you want to jump first, to avoid running of the edge and falling.
Another place I noticed it was when pressed against a wall where I want to jump up, then across. But instead I would need to run into the wall before jumping which doesn't feel intuitive.
A lot of this stuff is about game feel, which isn't really tutorialisable. And especially in a Jam, you want to hook people straight away, so familiarity is a good thing! I hope this all makes sense, I'm not great at explaining!
But overall, I really enjoyed a lot about your game! I had a good time in it, so no worries!