Of course the level of Fail could greatly depend on whatever strategy the programmers/grapists graphists used to get rid of the poor Video speccy's specificitiesfor the original game...
A monochrome game could remain monochrome or be recoloured on CPC... or only parts of it (only spriets or Tiles but not both... mostly only sprites.)
A coloured game with design-wise graphics (character based design) could be the exact same yet with even less colours...