I know, having your protagonist wake up in a constrained environment after an apparent accident with no memory is kind of the easy mode for thrillers. But what points Michael Polish's Amnesiac misses in difficulty it more than makes up for with its restrained, moody execution.

Sometimes he asks a question a little too pointedly, and she replies with some factoid as a non sequitur. He talks about his memory of the crash, asking about the girl, and she tells him about the missing size B batteries, or the first can opener, or the relative cost of bottle caps and bottles, or the number of chart-topping hits Conway Twitty had. The Man's addled mind is easily distracted, but ours isn't. We're hooked, wanting answers.

Bosworth plays the Woman with a stiff, buttoned-down beauty that reminds me a lot of Nicole Kidman, especially in the similarly-themed Before I Go to Sleep. She communicates the sense of something wrong under this person's glacial exterior with a marvelous reserve that matches the eerie calm of Aleks de Carvalho's understated, Satie-like score.
Unfortunately the mood only really lasts as long as the mystery does. As the truth starts to come out, inconsistencies start to pile up, and the Woman's behavior towards the Man makes less and less sense. We eventually learn much about what has happened, but little about why. The tension behaves like one of those optical illusions that depends on you observing it from one very specific, narrowly-constrained angle, and once you've seen the trick it doesn't quite work the same way again. But boy, does it work that first time.
Rating: 3 out of 5