Blood deserves better than other reviewers have suggested. It is a small movie yes but it is intense and filled with first-rate performances from an excellent cast. Bettany especially is on great form, but then he usually is, as a man falling apart. You believe these characters, understand their motivations and emotions, even as you watch them get closer to the edge.
We may have seen many of the cast in bigger productions but there is no sense that they are slumming it and even the smaller roles are played in an incredibly realistic way. It reminded me of some of the best noir movies in the way the plot is driven by the characters' reactions to one fateful action and the way the claustrophobia mounts as they struggle to come to terms with what has happened. Recommended.