A couple of years ago I briefly got into fooling around with Petaporon, a lovely little chiptune-y sequencer that runs in the browser and can save to rather small JSON files, or render out to MP3s or WAVs.
To say I am musically unskilled would be a grotesque overestimation of my capabilities, but nonetheless I enjoyed making some plink-plonks and beep-boops. Here's one of, IMHO, my better efforts, which I flatter myself to think has sort of a "2D platformer boss fight in a haunted toy factory" vibe.