Fun game! Has a few easter eggs, too!
If you want to change controls or volume, click the cog in the top-right (I didn't notice it either until someone else asked about it).
If you want to play more levels, there are user-made levels on Ellie's Discord server:
https://discord.gg/codebugs
You put them in the "StupidHeart\Stupid Heart_Data\StreamingAssets\charts" folder.