The Pegg/Wright/Frost Three Flavours Cornetto trilogy all marry some big genre with some smaller personal story and comedy: zombies and growing up in Shaun of the Dead, buddy cop and odd couple in Hot Fuzz, and now, alien invasion and growing up in The World's End.
And maybe that's why the film doesn't seem to work all that much for me, despite it getting good reviews and having some fun moments: didn't they already do this film before? I mean, the alien/robot angle is just that--an angle, a trope, a premise. Thematically speaking, the idea of a crisis forcing a character to grow up isn't all that new to this crew.
There's some interesting and good bits to this movie, including the recognizable and almost anti-heroic protagonist in Gary King, an addict and nostalgia junkie who feels his best days are behind him and is willing to lie and trick his friends to get back to his self-centered vision of the ideal world.
There's also the opening section, where Gary's voice-over about the best drunken day is revealed as a support group; and his assembly of the team scenes, which all cut out right before the person agrees to go with his crazy plan because (a) they really have no reason to say "yes" and (b) it's unimaginable that they'd say "no" given the premise of the film. And each person asks about Andy, which builds up anticipation for Andy's recruitment--which is the only one we see the end of and the only reasonable end: this person has no reason to want to go back in time, since he's built an adult life for himself, so of course he says no.
The film also nicely balances--at the beginning--the weirdness of the situation and the discomfort of these ex-friends. So, right before Andy confronts Gary about a terrible lie Gary told, Gary discovers the alien/robot invasion; which distracts us from the interpersonal tension, but only for a moment, so now these guys have two problems to deal with.
And there is something thematically appropriate about these alien/robots--the "blanks"--being preserved forms of younger selves, since that's Gary's problem: he needs to let go of his younger self.
Yet, the film also has a very shaggy elements, not helped by the ensemble cast where we clearly aren't meant to care too much about anyone but Gary and Andy. By the time we get to the aliens who are part of a network, part of Starbucking (buying up places with local color and turning them into chains), it feels less like a coherent movie about the dangers of holding on to the past. After all, Gary's problem is that he hasn't changed, but the town of Newton Haven's problem is a mix of "not changed, still terrible" and "changed to become ordinary."
And while it's fun to see a large man like Nick Frost turned into an action hero, tearing through alien/robots, his hatred of the town isn't really explored or explained. In fact, the more I think about it, the less I understand the character of Andy, which is really a shame, as he's the one whose anger really drives much of the film.