The sequel was a result of Arcand's longtime desire to make a film about a character close to death, also incorporating a response to the September 11 attacks of 2001.

Rémy and his friends of the older generation are still largely social-democrats and proponents of Quebec nationalism, positions seeming somewhat anachronistic long after the Quiet Revolution of the 1960s.

The father and son travel to the U.S. state of Vermont to briefly receive medical care before returning to the overcrowded and disorganized Quebec hospital.

Meanwhile, Rémy is reunited with his friends, including Pierre, Dominique, Claude and Diane, Nathalie's mother, and they share a conversation on their old sex drive and the gradual decline of their vitality.

[4] He had tried to write screenplays about non-Decline characters going to die for 20 years prior to The Barbarian Invasions, originally pitching the idea to the Canadian Broadcasting Corporation but having difficulty with the subject matter being overly sentimental.

[9] To research how his character would find heroin, Arcand contacted the Royal Canadian Mounted Police and met with them in an interrogation room, resembling the one in the final film.

He claimed the RCMP gave him the cellphone number of a Montreal detective, and when he called it, he heard shouting from a police raid on the Hells Angels, which resulted in the arrest of Maurice Boucher.

[12] The cast members from the previous film, including Dorothee Berryman, Louise Portal, Dominique Michel, Pierre Curzi and Yves Jacques, were easy to secure for the sequel.

[21] According to Box Office Mojo, the film finished its run on 3 June 2004 after grossing $8,544,975 in North America and $18,379,681 in other territories, for a worldwide total of $26,924,656.

[26] In Canada, Maclean's critic Brian D. Johnson called it not only satirical but "a moving elegy to a generation that defined modern Quebec and has seen its passions rendered obsolete".

[23] Peter Howell wrote in The Toronto Star that "It's the depth of emotions Arcand summons for his characters, and the way this superb ensemble cast bring them so vividly to life, that make The Barbarian Invasions a film not just to see, but to welcome home".

[30] A.O Scott of The New York Times wrote "what makes The Barbarian Invasions much more than a facile exercise in generational conflict is that Denys Arcand, who wrote and directed it, has a sense of history that is as acute as it is playful", adding "The rapprochement between Remy and Sebastien is beautiful to watch" and Marie-Josée Croze's "spooky, melancholy intensity darkens the mood of buoyant sentimentality".

[33] Jonathan Romney of The Independent wrote "The film has its pros and cons, but you can't fault it for ambition: it not only muses on life and death, but also undertakes fairly comprehensive philosophical soundings of the way the world is today".

[34] Peter Bradshaw, writing for The Guardian, disdained the movie, calling it "grotesquely overpraised", "shot through with middlebrow sophistication, boorish cynicism, unfunny satire, a dash of fatuous anti-Americanism and unthinkingly reactionary sexual politics".

[35] English Professor Peter Brunette wrote "its analysis of this state of affairs is all too often annoyingly rhetorical and, finally, altogether too facile".

[37] David Lawrence Pike criticized the use of the World Trade Center footage as exploitative, but said despite "the crudeness and vulgarity", the film had a "particular brilliance".

While considered part of a loose trilogy following The Decline of the American Empire and The Barbarian Invasions,[57][58][59] Arcand acknowledged in a 2007 interview Days of Darkness had more similarities to his less successful 2000 film Stardom.