More shocking than this film's ability to bore, is the fact that director Ben Wheatley made A Field in England three years after he made this one.
Kill List features an assassin, that is, a typically boring and unconvincing brand of antihero. Kill Lists character manages to sink to a new low of monotony-in-the-face-of-brutality, when the film not only forces upon viewer long sequences of unemotional killing, but equally arduous sequences of unemotional family life as well.
Multiple instances of spectacle execute gloriously, but don't bore yourself waiting for them. Hit fastforeward for the bloody chunks.
Also, intertitles lay about the Kill List. Intertitles are bad news. They make Inglorious Basterds look silly, and they do the same here.
The final act seems like a few scenes from Resident Evil IV, that is, a blend of Wicker Man meets Night of the Living Dead. You might argue that A Serbian Film was thrown into that blend, but that would mean you watched the movie. Sorry.