While undeniably containing many similarities to Saw II and Reservoir Dogs, Unknown boasts a unique (if contrived) central idea that lacks the necessary anchoring in reality to make it believable. Five men, all of them battered to some degree, awake in an abandoned mine (or refinery) with no memory of who they are or how they got there. As the story unfolds, they discover that two of them are hostages, which means the other three are bad guys. Even worse, the bad guys' accomplices are returning from collecting the ransom money to put a hole in the hostage's heads.
It's an intriguing premise, and writer Matthew Waynee touches all bases while not quite managing to exploit the opportunity for suspense inherent in the plot. Despite its short length (85 minutes), the time doesn't pass that quickly, even though the film is never boring. Everyone is understandably stressed and shouts a lot and they're all generally unpleasant to one another, so we don't develop any particular attachment to their characters. Given this, and the fact that there are some glaring plot holes (these guys don't have wallets?) the film falls short of its potential by some distance.
The cast is surprisingly good for what looks like a low budget effort, and they all perform well, and the story will keep you watching to the end to find out just who is who but, ultimately, Waynee adds just one unnecessary twist too many, leaving the suspicion that he wants to show us how clever he is as much as he wants to tell us a story.
