The oddly named \”Delta Episode\” is in fact a side story in Pokemon Omega Ruby and Pokemon Alpha Sapphire. It involves a potentially apocalyptic asteroid, the history of the Hoenn region, and a battle between Deoxys and Rayquaza in space. Yes, all of those things.
Pokémon Omega Ruby and Pokémon Alpha Sapphire introduce a new story, the Delta Episode, which reveals the history of the Hoenn region and thrusts Trainers into a quest to save the world. The Mossdeep Space Center, a research facility for studying space and rocket science, discovers that a giant asteroid is hurtling toward the planet. Trainers must stop Team Magma and Team Aqua from attacking the facility. Meanwhile, a battle in space is brewing between the Sky High Pokémon Rayquaza and the DNA Pokémon Deoxys… Trainers will also meet Zinnia, a mysterious girl rumoured to possess the key to the fate of the world. Zinnia wears a Mega Anklet set with one of the mysterious Key Stones, which allows her Salamence to Mega Evolve.
There\’s also this trailer for the Delta Episode which features \”moving pictures:\”
And Mirage spots, which allow you to catch a wide array of Legendary Pokemon. Which ones? It\’s version-dependent:
While exploring Mirage spots with Soar, Trainers can battle and catch an array of powerful Legendary Pokémon, including Raikou, Entei, Suicune, Uxie, Mesprit, Azelf, Cobalion, Terrakion, Virizion, Tornadus, Thundurus, Landorus, Cresselia, and Heatran. Encounters with Legendary Pokémon found in Mirage spots will vary based on which game is being played.
Not to mention the four Regis:
Regirock, Regice, and Registeel, the Legendary titans of the Hoenn region, make their return in Pokémon Omega Ruby and Pokémon Alpha Sapphire. They can be encountered after Trainers decipher ancient messages scattered throughout the region. After catching all three of these titans and meeting other special conditions, Trainers can encounter and catch the powerful Colossal Pokémon Regigigas, said to be the creator of the Legendary trio.
AND you can transfer Glalie from the demo, or Mythical Diancie from Pokemon X and Pokemon Y, to Pokemon OR/AS:
Trainers can obtain a powerful Pokémon in the Pokémon Omega Ruby and Pokémon Alpha Sapphire Special Demo Version and send it to their full Pokémon Omega Ruby or Pokémon Alpha Sapphire game via Pokémon Link: Glalie, an Ice-type Pokémon that can Mega Evolve into the menacing Mega Glalie. Meanwhile, owners of Pokémon X or Pokémon Y who receive a very special Mythical Diancie will be able to transfer it into their Pokémon Omega Ruby or Pokémon Alpha Sapphire game, and they can then get the Mega Stone that will allow Diancie to Mega Evolve during battle.
With all of this news on top of the game\’s recently explained Eon Tickets, Pokemon Omega Ruby and Pokemon Alpha Sapphire are shaping up to be much more than simple graphical remakes.
Source: Pokemon Press Release