It's a horror movie, but not it's not your usual horror movie. There is a fair amount of gore, but that is not the main theme of the movie.
It has a simple premise. Random people are trapped in what seems to be a never-ending maze of interlocking cubes on all sides. However, the main problem is that 2/3 of the rooms have deadly booby traps, so their progress to get out must be quite careful. No one knows how or why they've been imprisoned and they just want to get out and back to their normal lives.
It's an intense movie and it shows what happens to people when they're put into a seemingly impossible situation. Tempers flare, emotions go high, paranoia breaks out, and people start to go nuts. It's all a big mental problem, but the meeting of the minds doesn't form, which, therefore, makes unlocking the puzzle that much harder.
I found the ending of the movie to be the ultimate irony.
Watch this movie if you like to test and strain your brain's capacity for understanding things.
My favorite line: "This is a red room. I like the blue room."
