One of the most impressive things about this film is the atmosphere. Just watching it makes you sweat from the temperature (the camp's in Singapore), and from the tension and claustrophic feel. The acting as well is just amazing, with flawless and deep characterisation all round. Special praise to Tom Courtenay, whose skeletal elegance contrasts so wonderfully with Corporal King's loose form.
This is one of the best and most compelling war films I have ever seen, with a darker, more realistic view on the Second World War and people's mercenary nature.
Although the film is incredible, you absolutely MUST read the James Clavell novel it is based on, one of the best books I've ever read.
A must, in both mediums!