While Nintendo never released an adapter for playing NES games on the SNES (though the instructions included a way to connect both consoles to the same TV by either daisy chaining the RF switches or using AV outputs for one or both systems), the Super <answer>Game Boy</answer> adapter cartridge allows games designed for Nintendo's portable <answer>Game Boy</answer> system to be played on the SNES. The Super <answer>Game Boy</answer> touted several feature enhancements over the <answer>Game Boy</answer>, including palette substitution, custom screen borders, and (for specially enhanced games) access to the SNES console. Japan also saw the release of the Super <answer>Game Boy</answer> 2, which added a communication port to enable a second <answer>Game Boy</answer> to connect for multiplayer games.
Which other game system's cartridges could be adapted to the SNES?
Game Boy