Interesting idea! I included it in my Harvest Mouse Jam compilation video series, if you’d like to take a look. :)

I love games like this that are frustrating and unique and really test your patience. Its the type of game that requires time to learn the angle and hold time for the best speed run times. It has potential if more work is done on this game so well done.

It would be interesting to add a time counter and at the end show how long it took to complete as this type of game is best with speed run timers.
Also its universally accepted to have a main menu so if you plan on taking this game any further a menu is needed (I know you probably didn't add it because of time)
Adding obstacles  to get in the way do change up the game-play and make the game less repetitive.

Sound and music make the scene feel refreshing and enrich the experience.

Maybe abilities like a high jump or wall break when your spring is charged too tackle said obstacles (Game Idea).

I found a bug where if you try to charge a jump in the air just before hitting the floor you can charge again without touching the ground and get a little bit of distance in the air (Its not a huge issue and I tried replicating it again but couldn't for some reason).

(Please check out my game that I made for this game jam and give any feedback that you can thanks).