Should I make this so that swiping across the piano keys plays every note you swipe over, or should I leave it so the only note that plays is the first one you tap until you release it?

you should make a choice for both options, otherwise swiping.

Yeah, thinking about it I agree. Swiping makes it easier to get to the exact note you want, but not swiping lessens the chance it'll veer off to another note. Each key is only 8 pixels tall after all. Alright, that's what I'll do. I was having trouble thinking of what to put in the SETTINGS menu anyway :P

I vote for the second option because the keys of your piano look small and with the first you could play 2 notes by accident. In Litterbox is done like this even if the keys are big enough to tap them without problems. NFC MUseQ also do that and the height of their keys is 8px.

I've definitely experienced that problem while using my program here. It still will be very easy to make that an option though.

Besides, both have their downsides. Not swiping makes it so once you tap a note, you have to stop touching the screen then tap again to change the key played. Swiping makes it difficult to play only one note. Overall, yes, I think I'll just make it an option.