1. The game is too hard, straight away you're plummeted into a massive spiral which is a bit glitchy at the best of times. Maybe think of having a healthbar or checkpoints just so that it's not just a 'YOU LOSE' scenario.
2. the instructions screen froze for me for a brief moment and then finally displayed the back button after about 30 seconds.
3. Play through the game yourself and make sure all areas of it are fully working, there was a point where I was clearly in the white and yet I still died.
I know this seems a bit critical (especially to an 11 year-old) but the more you absorb the criticism, the better you'll get and the more thick skinned you'll become.
You could also try adding some public domain music aswell.
Good luck!