The acting is first rate, with Richard Brooks delivering the the goods as OD, the defacto leader of this group of recon soldiers.
The first person perspective throughout the movie adds to the impact and lends a realism that conventional cinematography wouldn't have been able to pull off.
The violence (it IS a war movie) is very realistic and disconcerting, which further involves the viewer in the movie. Moreso, this movie investigates the personal dynamics of the group of soldiers, set into the horror of the situation.
In retrospect, the story and characters are really nothing you've not already seen. The stereotypical archetypes are represented, the redneck, the scared short-timer, etc, but while you watch this movie, the combination of a documentary style filming and first person perspective, combine to make this film feel new and refreshing. Granted "Blair Witch" had a similar feel, but this pre-dated that film by 10 years and pre-dated "The Last Broadcast" (from which the "Blair Witch" was nicked) by 9 years.
If you can find a copy of this film. Settle in, crank it up and immerse yourself in it. It isn't the same as "the real thing": it isn't even close, nothing is. But it does let you glimpse into the world, without the fake slo-mo sequences, mood enhancing soundtrack, and trappings that separate you from "real life", and you can actually almost believe this IS a documentary.