I watched this film the last summer but I recently started using reddit. It's a mystery sci-fi film directed by Alex Proyas (The crow). It's about a man who mysteriously wakes up in a hotel and discovers the Strangers.
Overall I enjoyed the film really much, it's not long (110 minutes approximately) and fast paced. The dark tone of the film can't be found in many other films. The acting it's flawless. The CGI isn't very good and neither the action. But it's not an action film. There are some small twists in it too.
Generally I recommend it to everyone. It's one of a kind and it keeps you hooked the whole time.