The World's End: A Science Fiction Movie That's Also Pretty FunnyThe World's End isn't the funniest movie of the summer. But it's pretty darn funny in places, and it crackles with storytelling energy. And it's a good example of how to do a science fiction comedy that's actually proper science fiction, not just a comedy with science-fictional trappings.

Spoilers ahead...

Your usual science fiction comedy borrows some science fiction ideas and sort of trots them out for the comedians to riff off, or bounce off of. For example, the apocalyptic Biblical fantasy of Seth Rogen's This is the End is mostly just an excuse for some wacky "Exorcist" jokes, plus Channing Tatum in a bondage outfit. (As if you need an excuse for that.) The gold standard of SF comedies is probably the Back to the Future trilogy, where there's an attempt (however flawed) at logically consistent time travel, and you actually see Doc Brown drawing a diagram.

There are no diagrams in The World's End, but there is a decent amount of geeking out — without giving too much away, the otherworldly creatures in the film object to the label that everybody wants to keep putting on them, and there's some pleasingly geeky debate over the etymology of that label. The geeking out goes way beyond nerd in-jokes into actual discussion.

The World's End: A Science Fiction Movie That's Also Pretty Funny

And — again, without giving too much away — the crux of the film is a genuinely interesting science fictional conceit, which winds up tying into all the film's themes about growing up, and surrendering to the blandness of mainstream society, and the rise of "Starbucks"-style cookie-cutter stores. The thought experiment in this film isn't just a throwaway, but something we're meant to engage with, as the characters do.

Not that The World's End is breaking new ground, idea-wise — but it does tell a story that ends up exploring its science-fictional idea in a pretty thought-provoking, funny way.

So in The World's End, Simon Pegg plays Gary King, who was once a vaguely cool teen rebel who took his crew on an epic pubcrawl some 20 years ago. Now the crew is all middle-aged and respectable — except for Gary, who's still trying to rock the early-90s bad boy look. Gary guilts, bribes and tricks his old friends into reprising their old pub crawl, but their old hometown is a lifeless shell of the place they remember... and this turns out to hide a sinister secret.

I won't give away the sinister secret here, but to this film's credit, you're not kept waiting endlessly for it to be revealed. In general, The World's End keeps up a pretty spanking fast pace, unspooling the truth about the town of Newton Haven by the midpoint of the film. There are lots of cute comic bits, some of which work better than others and none of which overstay their welcome.

The World's End: A Science Fiction Movie That's Also Pretty Funny

And there is a lot of zany slapstick in the film, which is often funnier than any of the verbal humor. That's another way this film benefits from its science-fictional conceit — once you realize the town is full of glow-faced apparitions (they're in the trailer, so not a huge spoiler), there's plenty of scope for running and freaking out and fighting in the men's room.

And to the extent that the movie's science fictional story is there to provide a metaphor for the story of Gary King and his friends finding that you can't go home again, the SF elements complicate and problematize that story instead of just neatly mirroring it. The science-fiction ideas in the film help to explain why Gary can't step back into his old teenage dream, but also wind up showing how that teenage dream was a mistake to begin with.

The makers of this film — Pegg, costar Nick Frost, and director Edgar Wright — envision you eventually watching it after their first two collaborations, Shaun of the Dead and Hot Fuzz. But it might actually be more instructive to watch The World's End after a showing of Paul, Pegg and Frost's most recent previous collaboration and also a science fiction comedy.

The World's End: A Science Fiction Movie That's Also Pretty Funny

Not just because The World's End has a video-gamey slickness (especially in the opening) and a zippy pace that the Wright-less Paul lacks — but also because The World's End makes better use of its science-fictional widget than Paul did. The notion of two geeks finding an alien who inspired all our "grey" iconography is cute, but Paul never does anything truly clever with it, or transcends the "road trip" template. The World's End scores where Paul muddles along, as a comedy but also as a piece of science fiction.

The centerpiece of The World's End is definitely Gary King, one of the most unlikely heroes in science fiction history. He's sort of an evolution of the cocky cop that Pegg plays in Hot Fuzz, but he's equal parts loser and cool rebel. Most films would have gone for the easy win, either revealing that Gary King is purely pathetic or using the movie's creepy premise to show how Gary's refusal to conform is admirable. But The World's End keeps walking the line of showing how Gary is both a wanker and sort of a hero, right up until a somewhat head-scratching conclusion.

There are comedies out there that get bigger laughs than The World's End — I laughed harder at a few moments in This is the End, to be honest — but this summer especially, there aren't many movies that actually make an effort to delve into a science fiction premise as the basis of their story. As a comic piece of science fiction, this movie is pretty solid, and definitely worth seeing.