I played from the version you posted on GitHub, very nice for you to make it open source and also make an entry without a standard game engine:) I also really like the central mechanic, usually games have “slippery ice” as a random obstacle, so it was fun to play through well-designed levels that fully took advantage of it!!

Wow, definitely 5 stars for innovation! Using slow acceleration speeds as a game mechanic, and "spikes" that drain your timer faster instead of killing you outright, very clever design. Although I do think you could embrace that idea more by removing the bottomless pits and putting the spike-floor instead – that would require a change  of some of the levels, but it could lead to fun situations where you have to climb back up from the ground and you just barely make it. On a side note, I feel the current timer is waaay too lenient. It would be best to design a timer that's different for each level, and focus on hitting the "flow" region – not too easy, not too hard. Maybe you could have medals and make this a speedrunning-focused game? I certainly see the potential.

One lil detail: I noticed you have coyote time for jumping after stepping off a ledge, big plus; I'd also add coyote time for pressing the jump button before hitting the ground.