Pokemon Cosmic Emerald - Gameboy Advance (GBA) Purchase Options: [1] Custom Case + Game OR [2] Game Only (No Case) Description: This is largely a "quality of life improvement" type of ROM hack, and does not alter the main storyline. It retains all the features the original Emerald has, but adds several things to the mix to make it more fulfilling and fun to play. There is a moderate increase in difficulty, but there are rewards to compensate. Generation 1 - 3 Pokemon Available.