Right from the beginning I knew it wasn't going to work for me. The script seemed actorly, and the whole idea for the film came across as pretentious and long winded. One found no sympathy for the actors, except maybe for the Frenchman who didn't speak English (very wise). The film was too long, at times sleep inducing, and I didn't really care what happened in the end. Not a success for me.
This is an original film idea, 8 people take an exam with no obvious question or answer, they have to work out the question and answer in 80 mins with some rules they cannot break.
It all escalates quickly and actually the first 20 mins or so of the film are quite compelling but then it unravels. If you are watching closely there is a big hint of how to get the answer and then the film goes rather leftfield for a while before becoming a frustrating watch.
Ultimately it is a rather daft thriller/horror film with some loopholes in it but what saves it is its original premise. If they had rethought the screenplay a little more before starting the production it might have worked better...