AJNShelton on 27 February 2022
Hardware revision. Having games that can only be played in specific models isn't enough to distinguish two gens.
For eg: Switch Lite cannot play Nintendo Switch Sports nor Ring Fit nor Super Mario Party, doesn't mean it's not the same gen as the Switch.
When you put a GBC cartridge in a regular GB (or at least the revisions which doesn't include the stick that comes out when you boot the game, such as the Light and the Pocket), it says "no no no, please play this game on a Game Boy Color", it's very specific
