First up is a confession that I cheated here and watched the Redux version as opposed to the original, so my view may be slightly tainted by the additional footage - but I owned the Redux version so figured why not!
For the first two hours or so this movie is brilliant. From the opening scene with Martin Sheen struggling to adapt to life outside of the jungle to the murder on the Sampan, it shows everything you ever need to know about war (and not just in Vietnam) and explains the difficulties of it all so well.
The characters you meet throughout the movie are so incredibly real, that even when they are on screen for a short period of time you feel that you know exactly who they are and why they are the way there are. Duvall's portrayal of Kilgore in particular is just awesome: down to his lack of reaction to the dropping bombs and his refusal to give up on his lost surfboard, everything is taken into consideration.
Similarly the river travel scenes are beautifully constructed, showing perfectly well the fluctuating demands of the soldiers - massive periods of inactivity that are interjected with sudden demands that require instant alertness. Both the Sampan scene and the period just after they receive the mail are just brilliant.
You will probably notice however that I have only really complemented the first couple of hours (on the Redux version), and that is because I just don't get the Marlon Brando part of the movie.
When I read Heart of Darkness the character's backstory made sense, Kurtz had to be in that place and therefore his position as a demi-god to the natives made sense. In the film I just don't buy it. Yes Kurtz has gone rogue, and yes he may have disappeared into the wild, but why does he still continue to do battle in the way that he does? Why does he react to Willard the way that he does?
I just don't get it, which is a shame considering how good the film was up until that point.
This is a brilliant movie for at least the first two thirds and is then let down a little. Definitely worth watching for no other reason than you get to see exactly how a war movie should be made.