Added version of the previous post
The first trailer confirms the existence of the Wi-Fi Plaza in the games. Connecting to other players via Wi-Fi will also appear as similar to Platinum.
The trailer also shows the battle sprite of the Gym Leader, Jasmine.
Similar to the ones in Platinum, it is animated.
The Gym in Violet City is also seen with more elevation.

The second video shows that the Headbuttable Trees from GS will be back.
It seems that any tree is headbuttable. It is unknown if they all give Pokémon.
The second floor of the Johto Radio Tower is also shown.
The battle sprite for the legendary Suicune is also seen.
Lastly, the rare Munchlax will be available for capture in the PokéWalker.

The official site updated with a variety of new pictures.
However, in addition to this, it also confirms the return of the
Global Trade Station and the WiFi Plaza, same as Platinum.
Also, the Battle Frontier is in Johto.
The facilities and Frontier Brains are the same as Platinum.

First, Apricorns will be coming back.
However now, you have the ability to grow them yourself,
Using the SquirtBottle to grow them.
They're stored in an item called the Apricorn Case.
They can be given to Kurt in Azalea Town to have some special Poké Balls.
Here are their uses:
Fast Ball: Captures Pokémon that Flee
Friend Ball: Increases Happiness of Captured Pokémon
Heavy Ball: Captures Heavier Pokémon more successfully
Level Ball: Captures Pokémon of lower levels easier
Love Ball: Captures opposite gendered Pokémon easier
Lure Ball: Captures Pokémon caught with the Fishing Rod easier
Moon Ball: Captures Pokémon that evolve with the Moon Stone easier

-The Mystery Egg subset will also make a return.
The Pokémon inside the egg, however, has yet to be confirmed.
(It is unknown if the Egg you receive will still be Togepi.)
-Next, it reiterates Kanto's return in HeartGold & SoulSilver.
-It also confirms the National Park's Bug Catching Contest making a return.
This contest features you having to capture the best Bug Pokémon you can.
-It also confirms that the new area west of Cianwood City is a Safari Zone.
-And also, there is a new Battle Frontier style facility to the west of Olivine City.
-Rayquaza is catchable later in the game at Level 50, requiring Kyogre & Groudon.
-And Groudon and Kyogre are available, confirmed to appear in SoulSilver/HeartGold

Edit @ 10 August

-Apricorns also can convert into juice to boost your Pokémon's Pokéthlon stats.
-Three new Pokéthlon events have been revealed:
= Break Block (Your Pokémon breaking blocks using their hand, using the Touch Screen.
= Change Relay, also controlled on the Touch Screen.
= Push Circle. You control all your Pokémon at once

It also shows that you can customise the areas within the Safari Zone. Moving areas for quicker access should you need it to allow for easy access to areas if you're looking for certain Pokémon.