Mega Steelix and Mega Glalie will be in the ORAS demo:
Here are some more details about the demo:
Head to Hoenn Early with the Pokémon Trainer Club! Look for a Special Demo Version code in the October Pokémon Trainer Club newsletter!
Want to play the Pokémon Omega Ruby and Pokémon Alpha Sapphire Special Demo Version? Look for a special code in the October edition of the Pokémon Trainer Club newsletter. Then, use the special code in Nintendo eShop to download the Special Demo Version directly to your Nintendo 3DS or Nintendo 2DS system!
The Special Demo Version features a unique adventure where you can encounter cool Pokémon, including ones that Mega Evolve! Plus, you'll be able to bring reward items you obtained in the demo into Pokémon Omega Ruby and Pokémon Alpha Sapphire.
The premise of The Thieves and the 1,000 Pokémon is to befriend and collect Pokémon through StreetPass. You can use Pokémon to take on the band of thieves and their Pokémon by clashing in stampede-style battles to retrieve stolen treasure.
If you don't have enough Pokémon, you'll end up losing against the thieves, so you'll actually need to have quite a lot of Pokémon to get far in the game. The villains are characters who'll be appearing in the upcoming film, Pokémon the Movie: Diancie and the Cocoon of Destruction.
The trailer also mentions that there's a special something in store for those who play the game and take it to the movie theaters when the new Pokémon movie premieres. There will also be something special for those with Pokémon X and Y.