In Kega Fusion, the first demo ("Tech Demo") ROM doesn't work (it instantly crashes the emulator withsome dots on the screen). I don't know about Genecyst or Gens, but you might want to put a note on that ROM as well (it's already on the second rom)
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hmmm, sounds like you need a more recent version of Fusion to have them play properly. It's either that or the "BlastEm" MD emulator he suggested in the ROMs page itself