I'd honestly give this movie a solid 7.5, but I clicked 10 to try to offset the 5 pages of imbecilic, unjustified 1-star reviews. This is an interesting story, all of the acting is good to very good (even Ms. Diaz, who is totally out of her usual grinning-bimbo role here, yet plays it well.) The sets are perfect and the cinematography is consistently appropriately creepy. It's a fine morality play and there is *no* reason to explain the origin of the god/supernatural being/alien/whatever that's "running the show," so I'm glad the movie doesn't try. It's really irrelevant to the story, which is relatively long but quite compelling and summed up quite satisfyingly in the ending.
Before you decide this movie is terrible (or really, anything under a ~7.5) read some of the dozens of 1-star "hated it" reviews that are rife with misspellings, lack of punctuation and capitalization, and juvenile criticisms. Maybe the trailer was misleading or something -- I didn't see it -- but some of these reviewers were apparently expecting Terminator 4 or Saw 5 (one reviewer actually compared this movie to Saw! How utterly inappropriate and unrelated!)
Seriously, most of these reviews read like you-tube comments -- according to these "critics" this movie is too confusing yet too predictable, not enough action yet there's too much going on, too smart yet too dumb, explains too much yet leaves too much unexplained... oh -- and it's apparently a "waist (sic) of time." Do consider the quality and source of the reviews before taking them to heart. I'm afraid these 1-star kids failed to understand the phrase "altruism coefficient" and were therefore utterly incapable of understanding the movie's premise (despite adamantly claiming that they "get it" right before explaining how confusing it was!) If you know what those two words mean you will have no trouble understanding (and enjoying) this movie.
I really wish there were a reviewer reputation system here so I could be sure to ignore the rating of everyone who gave this movie 1 star forever.
See it for yourself and enjoy the fine presentation of an interesting couple taking an interesting moral "test" and facing the consequences. It's a good time, in my opinion.