I love what you were aiming for with this game! The slow and methodical movement with the jump being so interesting is a really big shake up of the platforming formula in a way I can get behind. However, there are some design choices that I think make this formula super frustrating at times. As much as I enjoyed it, near the end I was having to take some quick breaks.
1) Lets get it out of the way because everyone has said it, its the checkpoints. The slow and methodical game play is genuinely fun and interesting, but when you make us redo the same section from the start because I couldn't nail the unique jumps... well its an awful feeling. I'm sure it will be hard but you almost need to design a system that returns you to the last platform North was on when they jumped in order for this frustration to go away. And please don't reset us when we take damage from enemies. They have homing orbs!
2) At the end of the jump there is a little slide: remove this pleaseeeeeeeee. Tons of problems will go away if North stops right where they land initially.
3) While the slow walking speed is clearly deliberate there needs to be something to help speed things up. Especially for those sections where there isn't much to do except walk. Yes, I do know about the charge ability, but that's not what I mean. You could increase the speed just a little, add a small "dash" like thing to the attack, or you could make it so that there is a "sprint" where you power walk. There are tons of sections where I was just jumping around like a frog in order to get a move on.
4) And lastly, while I enjoyed the abilities that are in the game I think you should experiment with some way of utilizing them together. Like if you attack while charging its a cool dash you could use to get across gaps. Or maybe attacking right as you land makes you do an additional jump attack for flair and style. Idk just something to make them feel less separated is all.
These criticisms come from how much I enjoyed playing your game, not from a place of dislike. I think you chose a very difficult path to take with a game jam game and I appreciate that. With your talented art direction you could have done something very basic and boring and would have been praised for it. I can't wait to see how this game ends up if you decide to continue working on it!