This is the game jam game i played the most, not only from this jam, but ever (I think I'm at 3 hours and something).
Needless to say that i absolutely LOVED the game. I had a similar concept with my submission, not specifically, but the general idea of replaying the same platformer level over and over while gaining new abilities and power ups which allow you to take new shortcuts and faster paths. But your interpretation of this idea is just so addicting. I'm not kidding, i have to study this thing. At first i played for like half an hour and then i had to leave the house so i closed the game, but when i came back the curiosity got me, i had to know what was up there (or down there in the depths). so i started playing again. That's really rare for me. And my rational side was like "nothing is going to be up there for me, it's a jam game, and it's clearly just a score based game" but man i had to know! And eventually the platforming gets so precise and satisfying, and also you start thing about saving up harpoons, so you start thing about the route you want to take to be fast but also able to save resources for the last big jumps and... everything works together so well.
Eventually i got to (what i think is) the end (where there are a lot of jump through platforms on top of each other), i got there a couple of times but couldn't get all the boost circles while diving, so my highest lowest scor is about -200, i don't know what's the theoretical maximum-minimum,
Anyway, incredible game, so simple yet perfect, I will definitely try your other stuff. tomorrow. I played way too much of this now.