Fairly difficult game that overall felt fair. The hitbox on the spikes could use a tiny bit of tweaking but other than that the controls are responsive and the challenges are more or less on you rather than some terrible rng or praying the controls actually work. I enjoyed the fact that the crystals were of a non-linear difficulty. Level 3 actually threw me for a loop because it requires you to know that you can jump after a dash as long as you have not used your jump previously.
Good job to the creator, it's actually extremely difficult to create a platformer with responsive controls without having to go "I wanna be the guy" troll level for difficulty level... although the surprise spikes could qualify but they aren't too bad so it's forgivable.
The only bug I found was on level 15. Your hover lowers your character size enough to use fly to bypass the buzzsaw size basically allowing easy cheese at the beginning of the level. Not a big deal but maybe it matters to you?