Liked the idea, but at first I was completely confused about how to get orbs. I thought they were supposed to be flying at me at first. Also, if the player is just going to sit there and hold left click to grab orbs, it might be better to just have the player automatically pick them up if they don't have one. This might also help with teaching players how to play if they skipped the controls screen.
You might want to let the player see the controls after they start since the esc button doesn't do anything in game. I saw the enter key, and pressed it and couldn't go back to look at controls.