Short and intense. Those are the two words that best describe COD 4 for me. Exactly what I needed as a break from Persona 3 (level 60, to beat the final boss the FAQ I use recommends level 74 I think, so still some work to do there).
To walk (or rather fight) through Pripyat was interesting, they really nailed the look one sees in pictures and videos of the place. I actually stopped and spent a moment to have a look at the part of the level that resembles the area seen in this picture, that scene captured the feeling of this deserted town for me very well.
A bit strange that you immediately die when you enter the wrong spot when the area around the fair in Pripyat is one of the most irradiated. But that’s artistic licence of course.