The pair quickly discover a film being shot and befriend both a dwarf actor, and a crew member, the sensual Clémence Poésy, who offers Farrell just the escape he needs. The film escalates into violence, especially after boss Ralph Fiennes shows up, but is a dark comedy until then. It's really a film noir with some humor, and lots of swearing. The supporting cast from the hotel owner (Thekla Reuten) to a rude Canadian (Zeljko Ivanek, Emmy-winner for Damages) are all excellent.
The film has some artistic and even surreal moments, magically filmed. When you consider all the elements involved: a town as co-star, a dwarf in a surrealist film, drug-dealing con-artists, a hit on a priest, a kid-loving mobster - this turns out to be quite a unique script from McDonagh. Farrell won the Golden Globe for actor in a comedy (I think his most versatile performance to date, tho' Home at the End of the World was probably more difficult), and Gleeson (brilliant!) was nominated, as their onscreen chemistry was hilarious. Gleeson's performance is actually the more polished and professional, he's done this often. McDonagh's Oscar-nominated screenplay won several international awards, including the BAFTA®, for which the movie was nominated for Best British film.
Be sure to watch all the bonus shorts on the dvd, especially one with all the F-word outtakes from the whole movie, there's certainly over a hundred!
Update: Brendan Gleeson just won an Emmy in Sept 09 for actor in a tv film or miniseries, for "Into the Storm"