hahaha dude this app is great!! is perfect for children and adults of course!! this is my entry, a piece of 8 bit rock and roll hahaha.
I made it in less than 10 minutes, i think..For this one, i pick the piano and kit and hit the tempo on 159...
Hope you enjoy it!!

https://musiclab.chromeexperiments.com/Song-Maker/song/6425671848951808