Let me know how it works for you.
Works best on chrome. Just tested in firefox and the notes don’t ramp down in volume like they do in chrome, they just stop.
Not optimized for mobile either. Might work on those issues later but I want to move on to new projects. 
looks and feels great, i didn’t win at 20 - mine’s not quite as smooth https://mot01.github.io/FCC-Simon/
Your responsiveness is nice and smooth though, I need to brush up on that and incorporate it.
Did the user stories say to make it win at 20? I don’t even know what the user stories were, I don’t think we can access the legacy project pages that listed them.
thanks, the simon project and a number of the other legacy projects, plus some additional ones are in the coding interview/take home projects area - https://learn.freecodecamp.org/coding-interview-prep/take-home-projects/build-a-simon-game