Great mood, perfect for that kind of challenging platformer!
Now IMO the jump could use some coyote time, first person platforming has to be a bit forgiving as you can't see your feet. Also as you mentioned in your comments, the double jump isn't consistent.
You nailed one of the hardest parts of making a game by finding a consistent feel, I'm sure you can fix those gameplay details easily with more playtest.
Side note, try to make a web build for your next jam as people usually don't chance installing stuff on their computer.