Elisha Cook, Jr. did not receive an Oscar nomination for portraying George Peatty in The Killing.
Sherry of course is nothing but a greedy, shallow, adulteress who obviously has nothing but disdain for her husband. Cook is very good in their scenes together as he shows just how much he is controlled by his wife. Cook almost never seems to break his stare off of her as though George is looking for a single moment of adoration from her, something he never really does see. The way he leans and watches her, even the always sorta tender a way he speaks to her, Cook exudes such a striking desperation in George as he is obviously held in her sway simple because he desires his love returned so badly. The worst part for George though is that he cannot even talk big in the right way as he tries to get her respect by promising that he'll be rich soon. Cook's delivery though shows such a weakness in this statement and basically shows that George basically encourages Sherry to start prodding him for information. His attempts to backtrack or avoid the question though also shown by Cook to be such a difficult thing for him to do that him giving away the plot is inevitable.
With the guys Cook is good at playing George at trying to be like one of them, although with a noticeable discomfort. This only grows when the guys catch Sherry listening in and Cook naturally breaks down. There's a reason Cook played so many pathetic characters because he was great at it. He reduces down to that quick talking nervousness with such ease, and makes George so perfectly meek. After narrowly avoiding punishment from the other guys George even considers backing out as Cook portrays George's fear only growing. The only thing that brings him back is Sherry offering a bit of false adoration towards him, and Cook so naturally brings George right back under her sway once again. Cook though is not wholly one note and does well to have a subtle undercurrent of anger in George. He gives the sense that George is aware of the true nature of his wife, but his more base desires keeps him from really doing anything about. This comes into play when after the heist, Sherry's own plan goes into plan where she uses her lover to ripoff the guys. Cook makes George's finally snapping particularly convincing and rather powerful that results in a bloodbath leaving George as the sole survivor. Cook's best scene is perhaps when the wounded George stumbles home to Sherry who ineffectually attempts to hide her treachery. Cook is rather moving in this single scene as he plays it as George looking one more time to his wife for affection. He is denied once again so he shoots her and Cook is wonderfully woeful, in a good one of course, once more as he still expresses George's subservience though this time not enough for him not to take his revenge. Cook's work here is of course right in his type, but that's just fine, because he was good at being that type.