Here's what changed in Emerald
(Source: Serebii.net)
- Package is Green and has Rayquaza
- Set in Hoenn District, but with differences and new places
- RS heroes with new clothes
- People sometimes join in to battle against you with someone else on certain routes
- Pokémon have Animations Before Battle like in Crystal
- The Story Involves Both Team Magma & Team Aqua
- The Game is revamped and could be classed as a different game because of this
- Both Groudon & Kyogre Appear
- Battle Fronteir which has tournements of 7 major battles exists
- Battle Dome has tournements of 3 Pokémon
- Battle Tube which is a Special way of Battling
- Compatible with the Gamecube and Wireless Adapter
Thanks WeaponX for the release.
EDIT: DeMoNSTaR, if you have a cable like the EZFA cable, you can make a backup of an original game.