Okay I really like this idea like a lot. I think that you should definitely keep iterating on this! I think with some tweaking this could be really fun and satisfying. My main thing is the samples that are used are a bit harsh/have some noises in them. The notes that are added don't always harmonize that well together to my ears. I think if you got the generative music aspect/sequencer part down the rest would work really well. Keep it up! I would love to play a more refined version of this game!
Also I enjoyed the minimal art style, I think you did a great job of making it aesthetically pleasing with a small amount of colors and shapes!