This is a very good film for its story and plot, whatever others may say about a lack thereof. It is without dialogue, which allows the viewer to concentrate on the actual events of the film.
However, the film is lacking in several important aspects. First of all, it is not all that historically accurate. The events of the film are loosely based on a certain circumstantial incident that occurred in real life: two soldiers went out on some scouting mission or whatever and didn't return. They were found just over a quarter of a mile away a week later, dead. Nobody knows what happened; the film basically takes the premise and then creates a completely unrelated story out of it.
Second, although partially filmed on-site where actual military action took place, the so-called "canopy" is nothing like the real southeast-Asian forests.
Third, there is little actual action. Yes, plenty of stuff goes on, but there is little combat. This is a war film, in the jungles of Singapore, no less. There should be combat, because that's what happened.
Given the vast liberties taken with this film, the result is surprisingly good, though it feels a bit unpolished, if not rushed.
Worth the watch if you are not looking for accuracy but want a human-experience thing.