Publisher's description

A role playing game similar to all the other main Pokemon titles, the story for Pokemon: Emerald takes place over land and sea and pits you against the Team Aqua and Team Magma from Sapphire and Ruby. This time around, Pokemon will show off their moves prior to battle, perhaps as a sort of taunt.
Pokémon Emerald is a title in the Pokémon series of video games. It features the Dragon-Flying type Legendary Pokémon Rayquaza on the cover.
The game is an enhanced remake of Pokémon Ruby and Sapphire, adding to the third generation of Pokémon games. Like the games it was based on, the player controls a Pokémon trainer, whose general goal is to traverse around the Hoenn region and conquer a series of eight Pokémon gyms to earn eight Gym Badges, then take on the Elite Four, defeat the Pokémon League Champion and succeed him/her. Like Ruby and Sapphire, the game features the third generation Pokémon, but also adds some second generation Pokémon that were once limited to Pokémon Colosseum. The National Pokédex is also available without trading.
The game follows the same storyline as Ruby and Sapphire, but adds new elements such as the Battle Frontier, where the player can enter a variety of areas with different Pokémon competitions.