Hey, 3DNes looks a tiny bit amazing! As a concept it's brilliant, but the UI needs polish. Are you planning to release the source and/or accept external contributions such as UI improvements?
I'm aware you're charging for the software, at least for the latest releases, but most users are still willing to pay for an open source product, if only for the convenience of not needing a build toolchain. For instance Asesprite is open on GitHub and we're still buying it. :)