GameTrailers brought back fro mthe E3 game fair a whole bunch of videos of S.T.A.L.K.E.R. – Clear Sky, the FPS video game that presents the prequel to S.T.A.L.K.E.R. – Shadow of Chernobyl with its best elements.
Here is an example, but I think you should also follow the link to find some more (even HD versions of the same videos).
The only thing I would complain about is that the guy playing while being filmed is specially not a top-notch one and has to use God mode (he has not to be afraid of bullets since they have no effect on his health). Of course, if helps to present the game easily, byt realism is shatteredin those game sequences (in S.T.A.L.K.E.R. – Shadow of Chernobyl the adversaries are not always brillant, but you would not survive more than a second or two if you aimlessly wandered under their fire like that).