So, I've been watching the trailer several times today and I've started to notice some things, so I broke it down:
Male PC looking in the mirror:
It's in 3D! Duh. Looks like a cutscene the way the camera swings around like that. From the other scenes, it looks like the camera won't be controlled by the player.
On Route 3, approaching a town:
Looks pretty cool. Noticed a ledge off to the left. If that's one of the one-way jump-down-but-not-up ledges that have been in Pokemon since the beginning, why can't we jump up them again? Looks pretty small.
Swinging on the rope:
A gym? Rope/vine-swinging puzzle, obviously a grass gym if it's a gym at all.
Female PC running alongside a river:
Another route, nice scenery. Can't wait to see this all in 3D!
Male PC in a city:
Roller skates? The character doesn't seem to be moving fast enough for them to be a replacement for the bike, so maybe they're the new running shoes. But in other scenes you can see the player running. Also, back at the end of the street, it looks like a radio tower. A throwback to Gen 2? Maybe we'll see radio used heavily in these games like it was back then.
On a bridge heading out of a city.
Neat looking architecture in this game. Again, can't wait to see it in 3D.
Desert with mushroom-shaped buildings:
More cool-looking scenery. Also, maybe this is one of those ledges that we can jump down. That would make a little more sense.
Starters, battle scenes:
Finally! 3D Stadiumesque battles on a handheld! I've dreamt of this day since the N64 era! Also, Froakie can actually be seen physically hitting that Patrat in the very last attack shown in this part. The N64 wasn't able to handle representing that, so we got awkward animations where you would see a pokemon lunge forward then the other randomly flinch. So this is an improvement over the N64 (and, I do believe, the GameCube).
In a forest:
Random female trainer. Is she really following the player, or is she just one of those trainers that runs along a set path?
A wild Pikachu appeared (oh noes!):
So, old Pokemon will be catchable in these games (likely before the end of the game), so they won't be pulling a BW on us.
More battle scenes and gym scenes.
Looks like a Psychic gym, a Bug gym, and a Fire gym
Legendaries:
The Y-shaped bird:
Obviously a flying-type, but what about the other type, if any? I'm thinking dark. There's also always the possibility that they're going with part dragon for both of them, yet again.
The deer:
Hard to talk type for this one, but its antlers not only look like "X"s but they also resemble tree branches, and they showed it in a forest, so I'll bet that it's part grass.
Of course, nobody could have guessed Reshiram and Zekrom's types, or Dialga and Palkia's for that matter, so who knows.