This can only really be enjoyed as a sort of anti-thriller, a movie that lurches around trying to tick all the boxes of the visual tropes of the genre, but is utterly clueless about how they are supposed to function narratively.
It is packed with irrelevances, starting with the Italian location that gives it its title, and which viewers are taken to, irrelevantly, at the beginning and then again at the end.
Then there's a possible lost twin and his (albeit briefly) surviving sibling, who turns out to the most glaringly irrelevant thing in the entire story.
His mother is less a character to care about than a walking plot device, while her own father would have had a sign on his head from first entrance saying 'bad'un' even if they hadn't chosen to cast Brian Cox in this role and then given him an entire Chekhovian cabinet of pistols.
As for Claes Bang. We enjoyed him over Christmas as Count Dracula, but it showed how he needs to ham it up a bit to escape from the innate limpness of his anglicised persona...although of course this is what worked so well in The Square.