This is pretty good (ima assume your a begginer if you don't mind ;] ). It feels a bit empty, like a background melody would be nice but the beats are good none the less. Also since your son seems to want you to make him a level really had I'll scout you (scouting is when people go out and find unknowns, then if they scout them the user's work will be put in "brand spankin' new" category).
I wish you good luck, I hope your son likes it.
(Make sure to go back to your upload options and check the box on the bottom that says to use Gd's API)