Very, very, very good. A cult film. The very simple concept is perfectly suited to the mystery. The design of the cube is rich enough to be interesting for 1h30, but not too busy either. It remains mysterious with its complex door system. The progression in the film works very well, you can feel them moving forward as they have ideas. The function of the characters is well defined for the most part: the math student, the doctor, the cop, the gifted autistic, the king of escape... [spoiler] Only the architect, who apparently built the hull of the cube, is not very well defined. It is not clear at what level he designed the cube. He explains very poorly how he was contacted to make the cube and under what conditions. That's the only criticism I have of the film. [/spoiler] Otherwise, not saying anything at the end is fine. It's typically the kind of film, like The Truman Show, that can't accept a sequel. There were two sequels. Can you imagine a sequel to The Truman Show where we follow Truman's life outside the dome? It would be useless. It's the same here. There is however a Cube 2 and a Cube 3 where you can see the outside. The consequences are therefore of no interest, I advise against them.