Seven strangers volunteer to take part in a two-week test of a new drug entitled Pro9 at a remote clinic. Forbidden from using phones, Internet or even leaving the building, the group settle in for what they think is a straight forward fortnight. But on the very first night things start going horribly wrong as side effects from the drugs start taking over.

Writer/director Ian Clark’s atmospheric film survives and flourishes on tension and the audience not knowing what’s going to happen next. Strong performances keep things believable, particularly Alex Reid and Steve Evets, and the intrigue of the premise carries the film.

Unfortunately it just doesn’t do enough with the simple yet interesting premise, wasting bags of potential with too much waiting around. It doesn’t help that it brings to mind films such as Das Experiment, Exam and Fermat’s Room (to name but a few), which have done this sort of thing a lot better. And the ending just comes along without warning and fizzles out, hinting at an explanation that’s far more interesting than the one it goes with. The whole thing actually feels like it’s the first segment of a much longer movie, the ending of which has just been abruptly removed.

The film plays on a particular type of fear, one of distrust and the unknown, not to mention those who particularly don’t like hospitals or things of a general medical nature. This echoes the style of filmmaking employed; clinical and harsh, with no punches pulled when it comes to showing infections or injuries. In this way Clark is successful in creating a feeling of unease.

Featuring a premise that’s as intriguing  as it is downright scary (if you mentally put yourself in the character’s shoes), some effective moments of genuine terror and characters you actually care about, Guinea Pigs delivers much of what it promises. But once it gets to a certain point the novelty of the premise isn’t enough and it goes nowhere satisfying. Nevertheless worthwhile viewing for at least two thirds of its runtime, and you know what they say about two out of three…