At first, Ray and Ken being booked into a room for one seems like a joke, but then it's revealed that Harry only booked the room for Ken, expecting that he'd kill Ray as planned.
Early in the film, Ray rudely cautions a group of overweight American tourists against going up the Belfry of Bruges. Later in the film, when Harry and Ken are about to go up the Belfry they are told that it is closed because an American had a heart attack trying to climb it.
Early in the film, Ken tries to pay for the admission into the Belfry of Bruges with coins, but because he doesn't have quite enough, he pays with a bill. Near the film's climax, a mortally wounded Ken leaps from the Belfry, both because he is ready to die and to attempt to warn Ray that Harry is in Bruges. He throws the coins he was unable to pay the admission with down from the Belfry to clear the way. This plan would never had worked if he had paid with the coins earlier in the film.
The (quite racist) discussion on a "race war" between all the world's blacks and all the world's whites could very well be symbolic for the fight between heaven and hell - a central theme in the film. Ray casually asking where the Vietnamese fit in could, in turn, be a comment on Purgatory also being an in-between place. Ray commenting that it would be quite a sight to see could refer to the Hieronymus Bosch painting he and Ken saw. Both mention Purgatory even though it is not depicted in the triptych.
Ken's lie about Ray stating "I know I'm awake, but it feels like I'm in a dream." It can be applied to the climax: the movie Jimmy was filming depicts a dream sequence as stated by Chloe; the wounded Ray runs through people dressed like the creatures in Bosch's painting of purgatory that was discussed earlier in the film; Harry shoots who he thinks is a child, then kills himself.
Another interesting one about the finale: Chloe mentions that Jimmy's film is a pastiche of Nicolas Roeg's Don't Look Now, in which John Baxter is killed when the person he thinks is a child (his daughter who drowns at the start of the film) turns out to be a murderous dwarf, wearing a similar coat. In In Bruges, Harry dies when he shoots Jimmy, a dwarf who he also thinks is a child dressed in a similar uniform to the boy Ray killed — and who is playing a murderous dwarf who actually does turn out to be a child. On a more general level, both movies are also about people traveling in a foreign city trying to deal with grief and guilt.
The scene with Ken and Ray visiting a church seems at first to just be Ray misbehaving yet again because he hates being in Bruges, until you consider the fact that the accidental killing Ray feels so guilty over also took place in a church. Also, he kicks at the chair as he's sitting in the nave - the child Ray shot died because he was sitting in the nave and gave no indication that he was there.
Harry hopelessly losing the footrace to Ray seems to indicate he's out of any decent shape - but then one remembers that it'd only been a short time since he had climbed up and down the belfry of Bruges.
Ray is torn apart about killing the kid by accident, but has NO qualms about the original hit, which is murdering a priest. Harry, his boss, seems to be as good and as moral as a gangster boss ordering hits gets. With this in mind, there's one question: what did that priest do to earn Harry's wrath?
Explained in deleted scenes. That church was in the middle of one of Harry's house developments. The priest was just on the action committee against it.
Also in the deleted scenes Harry is strongly implied to have been molested by a priest as a boy, there's a chance he has some leftover hatred for priests in general because of it.
Imagine the reaction of Harry's family when they learn that he died.
Ray is already feeling immense guilt for accidentally killing a kid and by the end witnesses the deaths of Ken, Jimmy and Harry (and even tried to tell Harry not to kill himself). Assuming he survived when he was loaded into the ambulance, he'll probably feel even worse.
If the hit on the priest had been a success and the boy had not been shot by Ray then the boy would have been a close first-hand witness to the brutal murder of a priest. Ray would then have to live with having traumatised a young boy and leaving a witness to his crime who could identify him, one he would not have been able to silence there and then.
Ray is flippant when he tells Chloe that he shoots priests and children for money. But if the news of Ray's hit had filtered through to Belgium then Chloe would realise not only that Ray had committed such a terrible crime but Ray didn't seem at all bothered by it - an astounding irony given how much he is torn up by it.
Harry is using "dum-dum" bullets - either hollow point or soft point bullets - when he shoots Ray. But they would expand when they hit Ray, and would be far less energetic when they strike Jimmy.
Fridge Brilliance: Harry got ripped off when he bought those things.
