I have NEVER played a single platformer that out stands that level of comfort in movement. It's just right. Neither floaty, nor slippy, every jump leads you PRECISELY where you want to be.
The ability to repeatedly dash upwards AND downwards like a ninja in vertical shafts instead of simply wall jumping brings me pure joy.

The whole game is exceptionally charming, the mood is super relaxing, excellent use of accent color.
The sprite work is very detailed, every combination of action has its own variation.

The mechanics are a huge relief from the absolute standard of all video games. The enemies that don't have a normal attack don't have hitboxes, double jump and dash are available from the start (although I wouldn't be mad if it changes), projectiles can be salvaged from your missed shots, collecting coins is a hobby AND WATER SECTIONS DON'T EVEN FEEL RESTRAINING!

And although I usually don't comment on sound design since it's not my department, I must point out that every menu chime, chain clings, dash swoosh, bone clicks, bat chirps, water bloops and slime squelches feel right in there place and never distract from the main flow.

This is a concrete-solid foundation for a great, but really great platformer. The only thing I'd suggest is to take healthy development breaks, since the last thing I want to see is you getting burned out.
Now that a chunk of the fun part is done, motivation is likely to become sparse IF this is the thing you mainly work on everyday.

So I wish you the best in your career and a BIG THANK YOU for this demo! You've made my day :)