I'm happy to have paid for 3DNes, but a readme or installation instructions would really be useful. Can I put the 3dn files anywhere I want or do they have to be in the same folder as 3dnes.exe?

Thank you for the support!

Put it in the rom folder and matching its name with rom file. mario.3dn <-> mario.nes.

I have added an Attention section in the frontpage.

Thank you for your help. Good luck with future development.