Wow nice job -this idea went a lot further than I expected it to! 

Very difficult as well - I managed to get as far as this level:

There was one level in particular that I thought was really clever - the one where the portal is directly below you but there are ~5 floors of button blocks that you have to open. I thought I had to send 2 orbs with a specific timing gap, but had a nice "a - ha" moment when I realized the solution.

I thought the jumping felt a little/slow or unresponsive, and that there was a small delay between the button press and shooting an orb. But since the levels are designed to be played as-is it didn't bother me too much.

One very small gripe is that there should be some kind of level intro text - just a number would be fine. There is a a level I encountered about halfway through my play that looked similar to the first level, and I thought that the game had looped back to level 1.  I almost closed game because I thought I had beat it. Something like "Level 12" at the start would let me know that I am looking at a new challenge.

Anyways - nice work! I really enjoyed this