Nice! I like music, I like the mechanic (though it felt wonky sometimes), I like the aesthetics.
A fun game to speedrun. It'd be nice if the timer would be on the screen all the time, and not like right - you get the time only at the end.
Also, some sort of retry button at the end would be nice, so that people don't have to refresh the page every time.
Also, it'd be nice to add extra 1 tile of margin to both sides of the screen - I managed to click outside of the window way too many times.