The content is really good, but the jumping needs just a liiiiiiitttle bit more polish. Google Coyote Time and integrate it into whatever platforming engine you've got under the hood here. (You'd think with all the money people spend on the Asset Store, they'd include basic features that games have had since the 80s.)
I also noticed some other minor glitches... jumping while going through a door results in strange behavior during the fade-to-black, and sometimes when I'd drop into a shallow pit and try to jump back out again, I'd either hit my head on a nonexistent ceiling at floor-level and fall back down, or else I'd sort of clip into the corner so I'm standing slightly beneath the ground. (Can't walk, but can jump out of it.)
Frankly, the lack of Coyote Time is the biggest problem. If I die ONE TIME and it feels like it's the game's fault, that makes me want to go play something else. That's why developers invented Coyote Time and other "corrective" mechanics in the first place.
Fortunately, Coyote Time is easy to implement. Just look it up. I believe in you! Make this a great game that even Miyamoto would be proud of!