Pokémon Ruby and Sapphire

Pokémon Ruby and Sapphire are part of the third-generation of Pokémon games (also known as the gem generation from its naming - Ruby, Sapphire, and Emerald). It was also the first set of Pokemon games to be released on the Game Boy Advance, as Pokémon Gold and Silver were both on the Game Boy Color. This led to large graphical upgrades from the previous game, as well as a new storyline. Of course, as in every new generation of Pokémon games, there were also brand new Pokémon species.

Battling
Double battles were first introduced in these games, as well as Pokémon Contests, Secret Bases, and Pokémon Abilities. In Ruby and Sapphire and beyond battling enviroments, e.g Sandstorm would inflict damage each turn, and the ground was different. When their sales are combined, Ruby and Sapphire are the best-selling Game Boy Advance games in history. Separately, they are both among the top ten best-sellers for the Game Boy Advance.

The Bad Guys
Depending on which version you got you faced either:
 * Team Magma (Ruby and Pokemon Emerald)
 * Team Aqua (Sapphire and Pokemon Emerald)

Team Aqua were the ones who wanted to expand the sea and awakened Kyogre and Team Magma would expand the land using volcanic eruptions and awaken the legendary Groudon.

Extras
In previous games you fought the gym leaders, killed the Elite Four and mullered your rival/ champion. But in Ruby and Sapphire (and Pokemon Emerald) you go back to the hometown. And you get given a ticket to go to the battle tower/ battle frontier.

HMs
The previous TMs and HMs from previous games are inh the games but two new HMs were added:
 * HM06 is now Rock Smash (previously TM10)
 * HM07 Dive is added instead of Whirlpool
 * HM08 Waterfall has been moved from HM07

Remake
In 2005, the game was remade with the release of Pokémon Emerald. The game featured multiple upgrades, and you could also catch all of the three major Legendary Pokémon as well.