Simple and well acted, it has tension enough to knot the stomach.

The performances transcend the film's tropes, grounding it in characters that feel more complete than this subgenre often produces.

Clever and entertaining enough to recommend even to members of the 1%

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."