I love high-concept screenplays. When I heard the storyline for the movie Stealth – “an artificially intelligent fighter jet is struck by lightning and turns evil!” – I swear I nearly burst into applause. I’m not necessarily defending the films themselves; just the ludicrous poetry of the idea that drives them.

High concepts can quickly curdle, though. The movie blog I Watch Stuff crystallised this for me while discussing the poster for the latest Jackie Chan film Spy Next Door. The headline: “Actual Spy Next Door Poster Marks End of Spoof Movie Posters”. Take a look. It’s hard to argue the point.

For me, it’s the recent Bruckheimer blockbuster G-Force that hurts. A squad of celebrity-voiced, crime-fighting, wise-cracking 3D animated guinea pigs? When the worldwide landslide of promotion began, I thought: “You’ve got to be kidding.” Actually kidding, I mean – because G-Force looks exactly like one of those fake movies that act as an easy in-joke inside real movies.

The clip made available of the fake sitcom “Yo Teach!” was perhaps the single best thing about Judd Apatow’s recent (and disappointing) Funny People. It’s freakishly plausible. The script, the set, the laughter. You could drop it onto prime time TV and no one would notice. The same goes for the “MILF Island” clips featured on Tina Fey’s 30 Rock. It barely even functioned as a joke; more an only-minutes-away-at-best Reality TV prophecy.

(In both these cases, you can easily argue that the fake shows are cultural artefacts that are far more likely to exist in the real world than the actual shows that spawned them.)

This confusing play of reality-versus-parody leaves me suspicious of satire. Consider how studies seem to show that the reason Stephen Colbert is beloved by all sides of the political spectrum is that his refusal to break character makes him unpindownable. He’s a Rorschach blot in a classy suit.

I keep thinking of a quote from Steve Aylett’s faux-biography of science fiction writer Jeff Lint. In it, he writes that “satire was like scrubbing tombstones with a toothbrush, but honourable nevertheless.” Sometimes it’s impossible to tell whose tombstone Colbert’s cleaning.

And if Colbert’s fanbase can leave me feeling bewildered, something like G-Force mostly just leaves me feeling old. (You kids and your confusingly parody-tinged entertainment! Turn that music down!)

Old, that is, until I think back to the Teenage Mutant Ninja Turtles. It began as a parody of Frank Miller’s Ronin, but its stars became bona fide pop-culture heroes. When the Adolescent Radioactive Black Belt Hamsters inevitably appeared on comic book shelves soon after, I don’t remember batting an eyelid – despite the logic puzzle of parody squared staring back at me.

So to all the wise-cracking, gun-toting, celebrity-voiced guinea pigs out there? I may not understand you, but I salute you nonetheless. Just make sure you’re not struck by lightning.