Brendan Gleeson is usually natural, making the character he plays fit like a glovewhether the robust and humorous loyal buddy and the warrior, as in "Braveheart" (1995), or a quiet and subdued aspiring politician, as in "Gangs of New York" (2002), or a non-supportive father, civil war volunteer-turned-deserter, as in "Cold Mountain" (2003), whether the gentle, mentoring, culture-exploring hit man in hiding, as in "In Bruges" (2008), or on the other side of the law, the grouchy police sergeant with defiant, often dissident sense of humour (provocative in one-liners like "being FBI, don't you prefer to fight unarmed women and children "), as in this movie--and Don Cheadle, in the role of FBI agent Wendell Everett, a bit in the shade of Gleeson's Gerry Boyle, but nevertheless, sufficiently competitive ("Langley is CIA, I'm FBI "), neat and convincing in his performance as always. (I admit to have a soft spot for this actor since his impressive role of the manager of Kigali Mille Collines hotel in the movie "Hotel Rwanda" (2004), the very same hotel I have been frequenting for two months in 1995, just a year later to tragic events described in the movie.)
To a pretty frequent movie goer like myself, who hasn't seen a single en par (or better?) leading actor in this year that is rapidly advancing towards its end, it is hard to believe that very many better acting performances could be demonstrated in the remaining two months or so. Therefore, if Brendan Gleeson does not find himself at least among top nominees for any yearly awarded film prize, I'll have a problem finding such decisions just.
As a marginal note, I was lucky to watch this movie back home in my motherland, because having it subtitled was very helpful in order not to miss any of sergeant Boyle's wisecracks, delivered often in heavy Irish accent, and to understand at all occasional lines, uttered by marginal characters, spoken completely in Gaelic. Of course, point was not to be understood by English native speakers, but it was still interesting to know what usual "advices" (if not insults) were given to English speakers, though eventually not English (as FBI agent!) at all. As Irish colleague of mine once said "We don't sing songs in Gaelic so English people cannot understand how badly we talk about them, they know it already! We sing in Gaelic simply because that's our traditional language (N.B. official whatsoever), and songs sound much better and sweeter in it."