I didn't need any extra evidence or explanation to "believe" anything. The movie is so unabashedly ridiculous that I just accepted everything that it threw at me without a second though because of how amazing it was. But then, not everyone is in love with the patently ridiculous the way I am. Anyway, the film worked perfectly for me, someone who has never read more than 50 pages of the comics (yet) but not so well for my girlfriend, a die-hard fan of comic from the start. (She had a lot of fun with it though!)
I must say that I am mildly annoyed by the people claiming that this film's target audience was far too narrow, though. I am 22, yes, but I only have a very cursory knowledge of video games - the only system I own is a DS that I bought two months ago and before that it was a Gameboy and an NES that I received when I was in the hospital when I was five. Aside from that, there are a small handful of computer games I have played to some extent but overall I am largely unknowledgeable in this field, meaning that I don't fall into the supposed "gamer" target audience. The only reference I got apart from the most basic video game concepts (extra lives, money, experience, the set-up of a fighting game) was the use of the Sonic ring sound effect.
Then there is the idea that it appeals to the indie music crowd. Well, I know I listen to and like indie music some but I'm certainly not part of that subculture or whatever. Not to mention that my primary indie fix is Japanese - a far cry from Toronto.
And of course let's not forget all the 30-to-50-year-olds out there who saw the film and dug it just as much as I did, even though a lot of them probably had even less knowledge about video games than myself!
None of that is the reason I enjoyed the film. It contributed, yes, but my favorite parts were things like the vegan superpowers, the crazy ways one scene would cut into the next, the random absurdities abounding in every frame and just the general comic timing of it all. I loved the scene where the studio laugh track is used, for example, for its pure absurdity without ever realizing that it was meant to be a Seinfeld homage! Or Knives' forlorn "nooooooo!" in the background of another scene. Honestly, despite the obvious video game influences, video game homages were the least of what made the film entertaining for me.
Really, I think the movie could have a much broader audience than people think except that A) people write it off as being exactly what I just said it wasn't and B) lots of people aren't as ready to accept hyperkinetic absurdity the way I am(?). I don't know. Those are my thoughts, mostly.