From Glitch City Laboratories
A player has triggered the "This Game Pak is designed only for use on the Game Boy Color." message after triggering a Glitch Dimension
The message "This Game Pak is designed only for use on the Game Boy Color." is an error trap which exists in various GameBoy Color games, including Pokémon Crystal. Its purpose is to prevent players from playing Pokémon Crystal or another game on the original GameBoy, or Super Gameboy if it is incompatible with it. As a result, this error trap successfully blocks any game freezes or glitchy effects which may occur from doing so.
Many glitches which would usually cause a Glitch Dimension on Pokémon Gold and Silver, will instead display the "This Game Pak is designed only for use on the Game Boy Color." message in Pokémon Crystal because when the game resets due to a Glitch Dimension, it fails to check what console the player is using, and presumes that he or she is using the original GameBoy.
- Glitch Dimension