Ok, so you asked for feedback.

"Is the idea good or not" is not really the question. It's all about execution, especially with platformers and/or shooters. An idea will not make a game good, but thoughtful implementation would. I wouldn't say that the movement here is implemented well, but I like the choice of mechanics and the "kickstart" feels nice.

Specifically in this prototype, I was mostly frustrated with having to skip over 1-block platforms. This was probably what kept me from "getting into the flow", being forced into a precision-platforming segment before figuring out the metrics. Speaking of which, I think I often got frustrated because I had to make small jumps, smaller than I felt like doing, but only until I discovered the dash. 

That being said, I imagine this would be a much different story if this was not the start, but somewhere in the late game. As I understood, the idea was about getting through the same track decaying with each loop. Okay, why not start  with an almost uncorrupted track (think solid bridge) and then, after it gradually decayed over several loops, presenting us with increasing challenges, we could arrive at precision platforming we have in current prototype? This would also be backed by player being more invested in the game by that point.

Anyway, congratulations on making it through the jam! Don't linger on thinking you "don't know what's good" — you will learn, by playing your game and other games and answering the question: "why it feels the way it feels?" 

I think I get the feel you were going for (love movement based games) but there are some unpolished parts, for example spamming `Shift` makes you levitate. But it is fun.

Hard to control the character, maybe it's my problem XD. Corrusion through loop is a good idea!