The only problem I have with that is that there is no in-game footage. I mean the CGI is nice and all but I want to see some actual screens of Snake being played by someone.
Was the intro section in-game? It looked like FPS gameplay, and they had a caption for FPS as forget pre-rendered scenes. I agree that in-game footage is what counts.
I still don't buy it. If it was real in-game footage then why don't they show someone playing the game. I want to see someone throw the bullet up in the air and then catch it like in the trailer. I would also like to see someone lighting Snake's cigarette.
There is a video I saw of Hideo Kojima pausing the video, moving the lighting around, moving the camera, etc. all in real-time. Those ARE the actual graphics of the game.
I think the problem here is that the presentation looks too scripted after the initial FPS section. Particularly so given MGS' history of cut scenes throughout the game.
All of the work Kojima has presented in the past few years have been done using the in-game engine. These same type of arguments spread across the internet when the first footage of Metal Gear Solid 2 was revealed at E3. Folks insisted "That wasn't in-game. No way it could be!" Lo and behold that supposed "rendered" demo was the opening sequence of the final retail game and it was done as a completely real time, in-game engine cutscene. I've no doubt this is the case here.
Also, take a look at any of the screenshots of the trailer across the net. You can see the texture seams and aliasing in the screens. Usually a good indicator of this being done in real time as opposed to a CG tech demo.
There's a direct-feed version of the trailer over at the official site, and there's a short (~10 second) clip out there as a teaser for a 720p version. I read somewhere that the whole FPS section from the trailer was making fun of the pre-rendered stunt they pulled with "Killzone 2", and the trailer makes that quite obvious. However, all reports from TGS indicate that Kojima and friends were clearly interacting with the game apart from the trailer footage.