This has to be one of the most entertaining films for the price I've picked up on Amazon. It is most definitely a thriller, with a dense plot packed with plenty of action, but it is also a great SF film; not with spaceships, aliens, or hugely intrusive effects, but with small and subtle touches of advanced tech that are actually used not simply as props, but which are integrated into the storyline and action. A lot of science fiction films I've seen have had to focus on their super techno-fx, overawed by their own visual cleverness. This one just throws away the futuristic stuff, treating it as everyday and run-of-the-mill, exactly as these people who live with it would. The story is a bit confusing and in the end loses out a little to me as it moves from a more realistic tale to more of a fantasy, but I suspect that on a second watching it may well become clearer; for anyone who can follow the original Korean, it might be easier. The subtitles are generally very good, with just the odd typo or slightly confused usage. The acting is superb, and the characters are genuinely believable - I actually found myself caring who made it through the (brilliantly staged) raids and fights, which is rare in an action film. I enjoyed the music too, and the visuals were excellent. Well worth the money.