Capcom could do include those Mega Man platformer games on it:
Mega Man and Bass - released on Game Boy Advance handheld;
Rockman and Forte - released on Super Nintendo;
Mega Man Dr. Willy Wars (its Japanese version is Rock Man Megaworld) - released on Sega Mega Drive;
Mega Man Power-Up - released on PlayStation Portable handheld;
Mega Man V - released on Super Game Boy handheld;
Mega Man I-IV - released on the normal (monochrome) Game Boy handheld;

For Mega Man and Bass - only the USA version, Rockman and Forte - its Japan-only native, for all others - both USA and Japan versions!

I think those are all remaining Mega Man games that hasn't been released on the PC platform as I can tell!