Simplify the following text for a Grade 4 native English-speaking person.
Original: Cartridges intended only for Game Boy Color ( and not for the original Game Boy ) lack the `` notch '' for the locking mechanism present in the top of the original cartridges , preventing operation on an original Game Boy ( the cartridge can be inserted , but the power switch can not be moved to the `` on '' position ) .
Simplified: The Game Boy Color was the first Game Boy in color . It was also able to play Game Boy cartridges , which helped it sell better .