This is a Canadian film made by a German director filmed in South Africa concerning tunnel operations conducted by the 25th (US) Infantry division during the Vietnam war in Cu Chi province in 1968.
The film raises early on the usual Vietnam war film issue about "the new guy(s)" with liberal values coming into conflict with the reality of war when he/they join(s) a "tunnel rat" unit fighting the brutal subterranean war waged in the Cu Chi tunnel system. However this is not a film which considers whether the Vietnam War was right or wrong, but rather it deals with the narrower issue of whom on either side of the tunnel war would survive it.
As to the military aspects of the film, in so far as the film deals with the concept of underground operations in the Cu Chi tunnel system "the director gets it." The booby traps, punji stick traps, pit falls, water traps, rats, hand to hand fighting, danger of tunnel collapse etc in the tunnels are all portrayed.
In so far as the film attempts to portray iconic Vietnam War airmobility tactics or Vietnam War infantry jungle tactics generally, he does n't. For example, the director portrays a single unarmed Huey carrying replacement troops flying below hill-top level without top cover from a "slick," a "hog" or other air frame while it was being over-watched by the enemy and a forward operating base set in the jungle/bush without any clear perimeter, or a clear field of fire and with jungle cover up to the doors of every tent, sangar and bunker -with foreseeable consequences. Better military history or military tactical research prior to the commencement of filming would have been of benefit in this area.
The actors and actresses in the film are mostly unknown-which is all to the good in this case. Those playing the Vietcong/ Vietnamese roles generally give good performances. However the generally clean clothing and army boots, the pressed jungle green trousers and raser sharp trouser creases of some US troops in some "in-country scenes" are quite incongruous.
This DVD edition contains a bonus special feature which includes a revealing interview with the director during which he states that he was moved to make the film after having read only "one or two books" about the tunnels of Cu Chi. During the interview he also expresses the view that the Cu Chi tunnel system caused the US military defeat in Vietnam. This is undoubtedly a dubious and controversial view, but one which clearly has coloured the way in which he made the film: the VC are generally shown as emerging from their tunnels to annihilate US forces or annihilating the tunnel rats in the tunnels themselves. I cannot help thinking that it would have been preferable if the director's researchers had undertaken more thorough political and military historical research about the course and conduct of the Vietnam war prior to filming. The director also confirms that the dialogue was often adlibbed in shooting- which may explain some of the dialogue shortcomings criticised in other earlier Amazon reviews.
Nevertheless despite these criticisms,over all this film makes makes a good attempt to deal with an aspect of the Vietnam war that has received little or no cinema attention. If you have an interest in the military history of the Vietnam war and you are prepared to overlook the several inaccuracies in the film which would rightly upset or offend a Vietnam veteran, it is worth a look.