Here are my plans for platformers using that 7800Basic demo.
The Agathodaimon (Rastan Saga and Curse of Issyos meet Zelda 2, Gargoyle's Quest II, and Robot Ninja Haggleman 3. I was planning on having 7800XM support, but Curt Vendel's death shot the chances of that happening down.)
Kid Zenithian (Classic Mega Man, but with the ability to duck and shoot upward. See also Magical Doropie/The Krion Conquest.)
Ð838 (Metroid Clone)
Snáwcild (A Ninja Gaiden clone featuring a Demon Lands character whose name literally translates to Snow Child.)
Ildu (Wonder-Boy-esque platformer with Old English/Anglo-Saxon themes. Part of the Middanyeard series.)
Ghosts 'n Goblins clone.