You can make a song by changing delays in the script of the arrows as it will change the speed and rhythm. Then add music, a Winning/Losing bar and you're done! Colored arrows will go up on your side (Which has the orange cat) and once the arrow touches one of the arrows on the top, press the corresponding arrow key. After a while, the arrows will start going up on the blue cat's side, in which case you won't have to do anything. Then it'll switch back to you, and repeat. When you don't have a chance to click the arrow key when the colored arrows hit the arrows on top, your misses will go up by one.
Note: Sometimes even if you click the arrow key, your misses will still go up. Try and click the arrow key right before the colored arrow reaches the top arrows. Feel free to remix, add music, etc.! Huge thanks to Scratch for simplifying making this game (I'm bad at coding) and of course to FNF for the inspiration.