This game was tough! I'm not very good at 2D Platformers, but I perservered and managed to beat it! It's really mind blowing that a group of young kids helped developed this game. It's got a cute theme and the gameplay is pretty fun!
There are some places where I feel the game could be improved. The collision detection with walls or platforms you jump into kinda causes the player character to get stuck against that surface. This can be especially problematic during some platforming sections. Another problem has to do with the jumping. It seems the double jump is based on the frame you press the jump button. So if you want a higher jump then you have to press space on the first frame, and then immeditely after press jump on the second. For a game running at 60 fps, this is incredibly difficult. I think this could be easily tweaked to allow the player more time to maximize their jump with a little more room for error between jumps. (Allow more delay between frame input/add a buffer) I hope I'm on point with these problems, as I don't know what the source code looks like so I'm just giving my best guess based on what I played. Fixing these issues would make controlling the player way more tight so that players can precisely make jumps without errors.
Regardless, I had a great time! I hope you'll check out my video which has a few other tid bits thrown in there. I do rage a lot, but I watch my language for this particular video. Hopefully it's a fun experience to watch. Keep up the great work!