Fun game! I played to the end, and I especially liked the bosses and varied enemies. It was very challenging and repeat plays allowed me to improve in the various skills in the game, which is great. The challenges were thoughtfully designed throughout, and for people who like challenging platformers, it was well tuned. I spent a lot of time playing it so I'm curious to see more!
Some feedback that I hope is helpful: I almost gave up right after the second boss, and I worry that some players may stop there. The dash mechanic was hard for me to use even after repeat tries, because it wasn't apparent to me how it functioned. In further development of this game, you might consider a tutorial, or maybe using color as a visual cue : right now, when you get close to the orb, two arrows pop up pointing in opposite directions. If you were to color in red the arrow that shows the direction the player will go if they push A, I think players would figure it out more quickly. Once I figured out how to use it, it was a fun and impressive mechanic!
One other little hiccup I had: I initially beat the first boss, saved my game nearby, then traveled over to the right, picking up the elixir that gives you a third blue mana gem, and died at the second boss. It then respawned me back at the savepoint near the first boss. I was back to having only two blue gems. I traveled across toward the second boss, but this time the blue elixir didn't reappear. I'm not sure the game would have been beatable without that third gem, so I figured it would be helpful to point this out.
Great work, very fun!!