Fairy will be a new type. It is weak to Poison and Steel, immune to Dragon, super effective against Dragon, Dark, and Fighting, and Fire and Psychic-type Pokemon take half damage from it. (WPM Note: Fairy is confirmed, super effectiveness against Dragon is confirmed.)
Sylveon is Fairy-type. Some older Pokemon will be reclassified to Fairy, such as Mawile (Steel/Fairy). (WPM Note: Sylveon being Fairy and old Pokemon being reclassified is confirmed.)
Mewtwo has two new formes, not just one. Both are activated via items.
The professor’s English name is Patrice.
The Starter final evolutions are Fire/Psychic, Grass/Dark, and Water/Fighting. (WPM Note: Two days later [on Monday], the source informed me he had mixed up the secondary types of Chespin and Froakie’s final evolutions. This bullet point reflects the correction.)
The first Gym is Bug, the second is Fairy, and the fourth is Fighting. (WPM Note: First Gym being Bug is confirmed.)
A few attacks will be dual-typed. (WPM Note: Many people are interpreting this as an attack shooting out two types at once, but it could just be that the attack switches types under certain conditions or something like that.)
There will be a new type of battling style that Flying-type Pokemon and Pokemon with Levitate can participate in. (WPM Note: Confirmed. He also specifically named them “Sky Battles” but I missed putting that into the original post.)
You will be able to see a Pokemon’s EVs at a certain in-game facility. You will be able to boost the EVs through mini-games. It will take about two hours to get one stat to max EVs. (WPM Note: Gamefreak confirmed there will be greater visibility of EVs.)
Pancham evolves into Pangoro in the early level 30s. In order to evolve Pancham into Pangoro, you need to have one other Dark-type Pokemon in your party. Pangoro’s type is Fighting/Dark.
A Pokemon named Inkay evolves into Malimar. To evolve it, you have to hold your 3DS upside-down when it levels up (the 3DS has an accelerometer and gyroscope, so it can detect that). Malimar’s type is Dark/Psychic.
A Psychic-type Pokemon named Espurr (ESP + purr) evolves into Meowstick (Meow + mystic?). (Sounds like Psychic-type cats. Meowstick’s name sounds too similar to Meowth to me though.)
Like in B/W you have two rivals – one is friendly and the other is competitive. Your rival that is more friendly gives you his/her fully evolved starter Pokemon after you beat the game.
Another professor named Sycamore gives you either Bulbasaur, Charmander, or Squirtle.
Even though it shows the player riding on a Gogoat in the new trailer, players can’t ride on their own Pokemon. What was shown is just an alternate way of getting around Lumiose City and it only works with Gogoat.
HMs still exist but there’s a lot less of them.
Players will be able to see their Pokemon’s EVs (probably through the same in-game facility mentioned in the other post).
A new move, Belch, is a Poison-type attack that has a base power of 120. The user must consume a held Berry to perform it.
Draining Kiss is a Fairy-type attack that heals the user for the same amount of damage performed. It has a base power of 60.
If the previously revealed forme of Mewtwo can be said to look roughly similar to Mewtwo’s original design, the second supposed form of Mewtwo can be said to look roughly/vaguely similar to Mew‘s design.
In case you missed our correction the other day, the Starters’ final evolutions are Fire/Psychic, Grass/Dark, and Water/Fighting.