Wow I just saw the film last night and I was completely blown away. I really liked how the film was able to develop the characters from ordinary folks to psychotic guinea pigs within just 2 hours of the movie's duration. I was literally, as well as others in the theater, at the edge of my seat throughout the movie. Definitely very believable performances by the entire cast, especially that of Moritz Bleibtreu. I would also like to add that I was impressed by the various special camera movements and techniques that were integrated in the film like the sequence from inside "the black box". Very exciting, I highly recommend it!