Do you have a plan to make other synth gba roms or apps?
I'd love to see some sort of sampler synth (Not sure if that would be possible with the GBA).
Hell, I'd love to see this same workflow be ported to PC as a separate app with more synth types. One that doesn't require the Gba and has some sampling options.
I'm going to start working on a sequencer type app as well. But, if you beat me to it earlier (Still a newb with C), it would make me happy since I love this work flow and I just want to see this kind of thing release more.