For a film that’s almost entirely substance-free, “Scott Pilgrim vs. the World” is surprisingly enjoyable.

Director Edgar Wright (“Shaun of the Dead,” “Hot Fuzz”) and a big cast deliver a high-energy goof-fest that amuses without ever saying anything.

Based on Bryan Lee O’Malley’s series of graphic novels, “Scott Pilgrim” is about a Toronto dweeb (Michael Cera — who else?) smitten by one Ramona Flowers (Mary Elizabeth Winstead), a girl with punky Day-Glo hair and an attitude of studied indifference.

There’s a catch. Ramona informs Scott that she has had a colorful romantic past and that to win her hand he must battle and defeat her “seven evil exes.”

These range from a skateboarding movie action star (Chris Evans) and a vegan master of telekinesis (Brandon Routh) to a lesbian martial artist (Mae Whitman) and a sleazy Svengali who might actually be Satan himself (Jason Schwartzman).

Scott’s brawls with these rivals are patterned after the fights in video games. An onscreen counter keeps track of the score, and when Scott delivers a fatal blow, his opponent explodes in a shower of gold coins.

No, it doesn’t make a bit of sense. Get used to it.

Nor, for that matter, does Scott’s magnetism for women. The guy looks like and has all the personality of a fetus, but the ladies think he’s pure catnip.

“Scott Pilgrim” is so hip and ironic that it hasn’t time for anything as mundane as common sense or recognizable emotion. Ostensibly, it’s a romance, but don’t expect to actually feel anything in that department.

What the movie does have is an astonishingly high energy level. This may be the most caffeinated movie you’ve ever seen, filled with furious and ironic editing, eruptions of cartoonish special effects and a guitar-screeching alt-rock soundtrack.

There are also a handful of really funny supporting performers. Foremost among them is Kieran Culkin, who steals his every scene as Wallace, Scott’s uber-hip gay roommate. A running joke has the very straight Scott awakening each morning to find himself sharing the apartment’s sole bed with Wallace and an ever-growing assortment of men.

In the end, “Scott Pilgrim vs. the World” falls prey to its own diminishing returns. Scott’s big battles seem interchangeable, and by the time it’s over, you wish it had ended 20 minutes earlier.

There’s only so much you can wring out of detachment.