This film upsets me. It could have actually been brilliant without all the Y2K seasoning. It's just too fast paced, too loud, too overthought. This would have been quite a haunting experience if Hirschbiegel just slowed down, cut out about half of the dialogue and ALL of the cheesy German techno.
Remind me never to attempt Zimbardo's 1971 Stanford prison experiment! The film loses its potency through exorcising a present day worst-case scenario out of the notorious psychological case study. How quickly volunteers could assume the roles of 'prisoners' and 'guards', but a nuanced representation of these social and institutional dynamics would have revealed far more about human nature.
As has been pointed out already - an interesting and engaging movie, until it loses its way in the last inning. The look and feel of the movie was a pleasant surprise to me, though! The expressive lighting scheme and the cinematography are reminiscent of the 80s, but feel fresh and original when compared to the slick blandness of so many of today's movies.