Thank you Joel for taking the time to play through a huge portion of the game, and I really appreciate the honest and super helpful feedback. I definitely was trying to make this a hard to super hard platformer, especially the later levels, but the impression I am getting is that it is more unfair than hard at times. This is something I will definitely try and balance going forward.
I haven't played The Messenger but am always interested in any exploration based action platformer, so I will definitely give it a look. I also have thought about making the endgame levels just bonus experiences and not block off the progression as there's really enough content now where the first 5 levels + the 2 true endgame levels would be enough for this type of game.
Again, thanks to you and everyone who's taken the time with this game. It means a lot to hear your thoughts on this and I really really appreciate it.