Find Out About Old Pokémon's New Forms in Pokémon Sun & Moon

Although the above trailer for Pokémon Sun & Moon is over five minutes long, it does contain a lot of information to process.

It starts off by showcasing some of the original 151 Kanto Pokémon in new forms, showing how they've adapted to the different environment. A change of type, as well as look, is on the books for some of them.

Next, it goes into the next batch of new Pokémon:

Oricorio
Oricorio changes its form by sipping the nectar of certain flowers. Since it has four different forms—the same as the number of islands in Alola—it would seem that different Oricorio live on each of the islands.
Type: Fire/Flying
Type: Electric/Flying
Type: Psychic/Flying
Type: Ghost/Flying

Minior
Type: Rock/Flying

Gumshoos
Type: Normal

Fomantis
Type: Grass

Lurantis
Type: Grass

Mudbray
Type: Ground

After those, it shows off some of the rideable Pokémon - that's right, you can ride upon select Pokémon, including Charizard! This looks like an end to requiring an HM Mule on your team, so that you can Cut, Surf and Fly around the map.

It briefly mentions Trials, the completion of each will gain you access to the next island in the region. This appears to have taken the place of gyms from previous titles, as huge Totem Pokémon stand at the end of these trials, before pitting you against the Kahuna of the island (the leader).

Finally, it talks about Z-Moves - powerful attacks a Pokémon can only do once you are in possession of a Z-Ring, and both the Pokémon and trainer both holding corresponding Z-Crystals. Be careful, as they can only be used once per battle!

Pick up either Pokémon Sun or Pokémon Moon from 23rd November, only on the Nintendo 3DS family of systems.