The level design and environments were pretty good, but there were quite a few bugs / fiddly controls and hitboxes throughout. The dash in particular seemed to control in a very bizarre way. I couldn't figure out how to determine where I was going to go; there seemed to be some connection with the direction you're moving, but the instant snap to a quite far distance made it even harder to see the result of a dash. And the results also felt inconsistent? (I don't have a controller on hand at the moment, so I also had to use right-click for that, which was a bit unwieldy).
I fought the Angel of Death, which seemed to work okay until they got to a lower health, at which point the hitbox seemed to become nearly impossible to hit. But also, I could respawn right next to them with no penalties every time I died, so there was no real reason to not just throw myself into them with reckless abandon. I also would have liked to see some more opportunities for hitting the boss (i.e. a pause in movement or something), especially with the short attack range.
Once I got the double jump, traversal got a lot more fun, and the light ball's big speed increase felt nice as well.