I had seen both hollywood versions of the real story - both movies were a bit dull. This one though is on the veins of Nordi Noir and the real story the main spine of the story but there's more. The movie is dark,violent,talky,twisty and will hold your interest till the end provided you don't mind subtitles. Attention is needed at every stage as the story telling jumps beteen years but rest assured almost every question is answered by the end. It's a bit relentless although there were at least 3-4 occasions of dark humor. A lot of inspirations can be percieved in the movie from cinematography to camera angles,locations,etc with even a subtle but clear nod to the Korean 'Memories of Murder' (a VHS of the movie is shown as part of the story),Seven,Marshland, I saw the Devil,etc but that can only be a good thing considering the quality of those movies.
No hesitation in recommending this movie if you're into Nordic Noir or even dark,violent Korean films of the genre. Of the three movies based on the real Russian killer - this one ...for me ..hits the mark and stands independently as a very good thriller. Expect it to become a cult favourite.