I saw the Devil (2010)
Chosen by Andrew who had this to say: 'An unrelenting and brutal Korean revenge thriller by director Jee-woon Kim (The Good, the Bad and the Weird and A Tale of Two Sisters). The highlight of the film is a great performance from Min-sik Choi as a ruthless serial killer.'
A rather grim piece of exploitation melodrama (not enough his pregnant partner is killed but the forensics guy trips over and deposits her decapitated head in front of him).
It's well performed but a bit repetitive and over-long. The revenge angle is at least interesting (though the old saw of hunter and hunted being two sides of the same coin is trotted out again), and after appearing to wimp out of giving horrific consequences to Lee's revenge plot (a couple of people Choi kills after being released are murderers/kidnappers themselves bizarrely) takes it to it's extreme at the end in a way that thematically works but is still dramatically too much.
Not a pleasant film by any means.