For example Amiga and most 16-bit consoles could just have two (or more) playfields (like layers or screen size sprites) superimposed on each other. For the gam

For example Amiga and most 16-bit consoles could just have two (or more) playfields (like layers or screen size sprites) superimposed on each other. For the game code those pixels would still be "black", well, transparent, even with background graphics showing through. No blitting required, playfields were drawn by the display hardware at scanout.