Why remove the trailer scenes?

[Alardem]

I've experienced something similar with FEAR 2's trailer:

First footage of 'Project Origin'

The final version of the game featured events similar to those shown in the trailer, but in a rather different order, and the pacing, sound effects and lighting had changed to the point that many people were underwhelmed.

Suffice to say, I've come to not take trailers too literally. I was a little disappointed when the scene from the second trailer was reduced to a rather stupid cutscene devoid of any danger, but not enough to feel cheated.