I agree. It looks like they incorporated a general bright and colorfullness into their artstyle because that would go well with their technical limitations. It's not full of gritty detail everywhere because with the amout of texture and geometry variety in there, their memory and production budget just would't be able to keep up. Instead they compensate with a strong and characteristic lighting and some sort of dynamic GI to make stuff pop out and feel realistic. The tod also makes the game feel very 2012 in some way. Rockstar is definetly out to something special here.
Things I observed:
Old guy's whiskey's glass lights his hand with some moving caustics. Probably faked by the artist's atention to detail, but maybe procedural? Also in that same scene, there seems to be two shadow casting lights there, clearly noticeble in his chair. Again, its either an artist specifc light added for that cutscene, or GTA's universe could have two suns around earth's atmosphere.
Very next shot, notice the abrupt light changes in the train carts as they go under the bridge (happens when the whole cart is shadowed, it dims to a darker ton entirely pretty fast). My wildly speculative guess is that this is a side effect fo their GI working in a per-vertex fashion, something I find plausible because the same was true in LA noire.
On the molotov's scene, in the shot inside the house, the flames do light the enviroment. Very realistic fire too. When hose explodes, destruction physics seem impressive, but pretty doctored. Just the bottom floor's roof trembles as that is the most visible one, top roof stays stactic.
"Do you know where Berto's ( is that it?) Beach house is?" Yet another moment where the double sun effect is more evident. Is this actually procedural? Not exactly physically correct but pretty comon in movies too, to better define volume.
Boy hangin on the boat's sail scene: Everything is severely motion blurred exept for the boy, they blue shirt black guy on boat, and the red conversible, which have no motion blur at all. Makes them pop out somewhat, it pushes player's eyes into them, but looks pretty unatural as well. Also noticible on past screenshot of the same black guy (I think name's Trevor) hanging at the side of a truck)
Safe explosion: Lots of particles, people seem to like that. They do colide with env. geometry.
Rappel scene: This one got me intrigued. You can see actual objects and even a moving NPC incide the bulding through the windos on multiple floors. Again, that could happen only on very specific, artist defined building, only on missions where necessary. Still cool.
Skydiving: wow. The way this scene was put into the trailer was pure genius. It makes it feel like "oh, yeah, you can also drive your way out of a cargo plane and jump out of your car's door in mid-air, no big deal" Technically speaking, we get a glimpse of how the city looks from very high up, the clouds do look acurate from the top too. Probably more doctoring, things just can't be that robust in a game this opened.
Train crash: Particles particles particles. Fog inside train's tunnel are pretty incorect. Oh well.
Throughout the trailer, cinematography is exelent. Scene lighting plus camera and actor's positions always makes them look dramatic, and their faces are always well lit. It almost looks like they have a spot light on the old dude's face most of the time.
History tells the game will definitelly be way less polished then the trailers makes it look. Actual gameplay will suffer with pop-in, weird facial animation, glitches, and so on during mostly the entire game and its real time cutscenes. Yet it won't be too far from what the trailer shows, and that is hell of promising.