Hey nice game! Seems too difficult for me, but I'm not really a skilled player at these kind of games. It isn't easy to make a full game within the week given at this 1-button game jam, but I think you did well.
To start, your game has great art, animations, and the one soundtrack I noticed. I love the tempo, the beats, and the general design of everything you currently have. The game was too difficult for me to really progress much further, but I'm not skilled at these games anyway.
Character Improvements: I noticed unlike most (finished) games of 'mario' like style, have a buffering zone after the character isn't grounded that you can still jump. I'd recommend adding this feature, as it will likely decrease the difficulty of the game and making it feel better too.
Recommendations: Instead of just restarting the level, you could add checkpoints and like 3 lives. Lose a life each time you reset to a checkpoint, and when you lose them all display a death screen with maybe a score or something.
Fantastic job on the game!