Factual error: Oswald says that "Vermeer only painted twenty-six paintings and three of those are dubious." There are in fact thirty-five known to be extant (one recently stolen) of which only one is regarded as dubious. In addition, there have been descriptions of six (or possibly eight) others that seem to be missing.
Plot hole: At the end of the movie, snails collect on the apparatus on which Oliver and Oswald have set up a time-lapse camera to photograph their decaying bodies, eventually short-circuiting the camera and wrecking their experiment. As they had previously (01:34:18) set up similar apparatuses in the same area (Alba's country estate) photographing other decaying organisms, why didn't the snails collect on them? (Pleasant film, huh?)