Going to see this was in large part an exercise in trying to get the hang of what the kids like these days. I knew in advance that it would really require a working knowledge of things like video games (which I don't have) to get most of the jokes, and I gathered that the whole thing was probably largely about the experience of being young (which I'm not). However, I write and edit roleplaying games material for a living (of sorts), and this is clearly the geek thing of the moment, so I feel a certain obligation to keep up with some of the references.
Plus, I can't help but feel a certain admiration for the work of Edgar Wright, going back to (and still largely focused on) the classic TV Spaced, so I was curious about this movie.
And, yes, it was genuinely entertaining, even if I didn't happen to know exactly which video games involve those particular martial arts movies, or defeated opponents disintegrating into coins, or whatever. (And, okay, no, I haven't read the Scott Pilgrim comics either, mea culpa.) Like Spaced, this film finds the essential, universal comedy in a specific and personal situation - and doesn't bother denying the essential comic gormlessness of the archetypal slacker-geek - so one doesn't need to get every reference to get enough of the jokes. I laughed, I might have cheered a bit, I didn't feel that I'd wasted my time.
The only thing that I would say is that the plot suffered slightly from the standard problem of slacker-romantic-comedies; with a male lead who's a bit of a clueless loser, it's hard to see what the self-assured, assertive love object was supposed to see in him. Admittedly, in this case, said object of desire had her own problems - the standard reading of the plot seems to be that it's really all about helping her to get over her hang-ups and to get rid of the ghosts of her past - but at least those are adult sorts of problem; compared to somebody who'd moved from city to city, learned to at least recognise her own emotional failings, and acquired some kind of proper paying job (making her "kinda hardcore"), Scott Pilgrim is just a child. Compare and contrast, say, Spaced, in which most of the characters have some kind of viable employment while all being at approximately the same level of psychological incompetence.
But, heck, the visual gags and stylistic tics were quite funny (see the aggressive female character who's perforce acquired the ability to generate her own verbal censorship effects) and occasionally clever, as were some of the one-liners (such as their drummer's introductions to Sex Bob Bomb's various performances). And I spotted the Princess Bride reference. If we're going to have stylistically flashy slacker-rom-coms for the video game generations, this will do for a start.