The Stanford prison experiment was about group dynamics when people were assigned roles of prisoners and guards but the movie only revolves around the two main characters most of the time, with others being almost entirely absent. As group dynamics do not really get into play, they miss many opportunities for personality development, which is what made the actual experiment interesting in the first place.
Due to the complete lack of character development (with one exception) the movie feels rather dull and the behavior of the characters, as well as their backgrounds, suggest that the researchers had knowingly picked individuals who had mental or other problems in the past. Even though the plot is about as linear as it can get, it is still full of holes.
The German version is much better, not because The Experiment is a remake but because it is dumbed down way too much. A typical reality-watching simpleton may find the remake easier to follow, though.
Even with its flaws, I give it 7/10 because the basic premise is interesting and the movie is refreshingly different. The set and the cast were certainly good enough.
