Good topic... I saw the Tim Sweeny interview, G4, and when he was asked about the Kill Zone 2 trailer he said that it was a "movie" of the game but he said that 50% of the trailer was done by the game engine and rest was done by CG.
BIG WHAT IF...
Most of the PS3 games 'play', I mean you have the controller and game, were some of the graphics are produce by the game engine and the rest is CG.
Remeber FF 8 on the PS1? Although it was quiet easy to tell if it were CG or not, Square was the first company to do this technique. You could move your character around during the cut scenes / CG parts. It was really cool at the time but the game characters would leave HUGE and noticable artifacts on the CG back round.
Now I'm not saying all PS3 games are gonna implement this but this could be the reason why Kill Zone 2 looks like it came from the PS5, unless it's really from the PS3

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