Martin McDonagh: One of the Coen Brothers' Pseudonyms?

Last night, I watched the Golden Globe winning comedy "In Bruges". Directed by Martin McDonagh, the film stars Colin Farrell and Brendan Gleeson as hitmen hiding in the town of Bruges, Belgium. After watching it, I noticed many similarities to the Coen Bros. films.
One thing I noticed (and the most coincidental of them) was the music, composed by Carter Burwell. Coincidentally, he has composed the music for every Coen Bros. movie besides "O Brother, Where Art Thou?". Another similarity between "In Bruges" and their films was the themes explored. In "In Bruges", one major theme is keeping your word, shown when Henry (Ralph Fiennes) shoots himself after killing a person, haven said earlier that he would do that. This is a lot like "No Country....", where Chigurh keeps his word on who he vows to kill.
A third similarity is the tone. Much like "Fargo", "In Bruges" featured a self-mocking sense of humor which eventually morphs into a bloody (though never gratuitous) ending. This dark comedy is a staple of the Coen Bros. that is also featured here.
So, was "In Bruges" really directed by the Coen Bros. and not Martin McDonagh? Of course not. While there were many similarities, "In Bruges" lacked the Coen Bros. very dry, witty, sense of humor and instead relied on Ray's angst and hate for the town of Bruges for the majority of the humor.