I really liked the look and feel of this game. The art style was crisp and the music fit the environment really nicely. The environmental lighting was also super slick, really good implementation there. I was also generally pretty pleased with the controls at first, I felt like I had the right amount of control over my character and my jumps/start + stop speed felt natural.
However (time for feedback/suggestions),
1. The controls become pretty complicated after a time. The sprint and float both felt good (although I wish there were an indication that the float is about to end, maybe a brief flash or something), but once I unlocked the Fire ability I found myself doing some mental gymnastics trying to control my character (fire + double jump + release fire + hold jump to float was a lot to process in the very short span of a jump).
2. Related to the controls and how precise a lot of the jumps were, there were times when I wasn't sure if I was meant to progress in a certain direction or come back when I had more abilities. In the beginning on the way to the Sprint upgrade there is a super tight jump between two of the disappearing blocks that sort of made me wonder if I was exploiting the game rather than progressing naturally. (the jump came super early in the game so it felt more difficult to pull off than anything around it which is why I had that doubt).
3. There's a lot of content in this game, a lot of rooms to explore, but I wish it had evolved beyond increasingly difficult spike puzzles. I was generally okay with the lack of enemies cause this clearly was more of a puzzle solving/exploration style game, but in that case it needs a few more hazard types to avoid feeling too repetitive.
Overall I enjoyed the game quite a bit in the early stages but the controls/spikes got the better of me towards the end and I wasn't able to complete it. That being said, it feels like a super strong foundation for something really fun and the presentation itself is top-notch, so I hope you keep at it. Good job!