No no, that' s exactly the case. But as with every other MGS game, the cutscenes are of far superior quality to the actual gameplay.
Because it' s a cutscene and doesn' t require things like AI, it frees up processing power and enables developers to add post production effects.
It' s the same with Gears of War on 360 where some of the stuff that we' ve seen is obviously from a cutscene and looks of higher quality than the game looks when you' re playing it. This is from a cutcene...
...and the thing ingame doesn' t look like that.
I' m not saying that MGS will look bad ingame, just that i don' t expect the game to look as good as the cutscenes do, though as you noted, with 18 months left of development, the gameplay could very well look like the stuff we' ve seen so far with the cutscenes looking even better.
However, what we' ve seen so far has been little more than a tech demo, or at least that' s what i believe. It' s not an early build of the game, just an early build of the engine showing off what can be done.
I doubt we' ll see anything ingame at E3 either, just another cutscene like they do with all MGS games.