How sad is this?

A film with more than the usual spoiler issues. Talking about it in any detail feels akin to handing you a gift-wrapped present and saying, "I hope you like it -- It's a thriller about a diabolical secret experiment."

Strong acting helps the film overcome an uncertain premise and create characters that hold our attention absolutely.

The film never slows down or bores, plunging from one harrowing sequence to the next.