Some — not all, but some — of the folks showing up for their second paying job in the “Sonic the Hedgehog” universe let us see their boredom.

Actors are careless about their sightlines when interacting with a digital effect. The three-writer screenplay is such a cut-and-paste job on the instantly forgettable script that a character riffs on that.

“I don’t want to die like this! It’s DERIVATIVE!”

Of course that’s a line delivered by Dr. Robotnik, Jim Carrey. And of course Carrey brings his best efforts to this nothingburger — sorry, nothing chilidog — of a blockbuster. That’s professionalism.

As “Sonic the Hedgehog 2” blows up the box office on its opening weekend, it’s worth reminding one and that while this may be cheesy, inane, and only suitable for the ten-and-unders, you’re saving the cinema, the movie-going experience, and getting kids back in a habit that could easily disappear by making it, releasing it and going to see it.

This is important work. Even disposable, dully-written and stupidly-overlong collect-a-check gigs have their place. Carrey, who isn’t working nearly enough these days, is one of the participants here who gets that.

“Sonic 2” delivers a new villain — Knuckles the red Porcupine, voiced with the expected menace and panache by Idris Elba. And as you saw at the end of “Sonic the First,” Tails the orangish Fox (Colleen O’Shaughnessey) is here to give the Hedgehog a gloved hand.

Dr. Robotnik has to engineer an escape from his mushroom planet exile.

There’s a “master emerald” to be found and the race to get it includes snowboarding and running on water — because Sonic can’t swim.

And Sonic’s human adoptive parents (James Marsden, Tika Sumpter) have a wedding to attempt to attend in Hawaii. There’ll be hell to pay if Rachel (Natasha Rothwell) doesn’t get “a ring on it” from handsome Randall (Shemar Moore).

That gives Sonic just enough time to get into mischief, meet his new nemesis and ready-made sidekick before he ruins said wedding on his way to saving the “ultimate power” master emerald from the villains.

It’s based on a youngish-skewing video game, so expecting much in the way of story or stylish direction would be foolish. The effects are generally good. The constant fights and chases are what stretch this out to over two hours running time.

A few jokes land, almost all of them out of Carrey’s over-mustached mouth as “a featured player in this theater of the absurd.”

“You want something done right, you have to hire someone you can push around.”

As violent as this sometimes is — cartoonish, bloodless violence — the messaging is harmless enough, all about “families stick together, no matter what” and pledging your loyalty with a “power bump.”

So do your part, take the kids and save the cinema. Because every parent needs a reminder of “the things I give up (like two hours of your life) for my kids,” and there really isn’t that much here for anybody else.

Rating: PG, cartoonish violence, innuendo

Cast: Jim Carrey, James Marsden, Tika Sumpter, Natasha Rothwell, Shemar Moore and the voices of Ben Schwartz, Colleen O’Shaughnessey and Idris Elba.

Credits: Directed by Jeff Fowler, scripted by Pat Casey, Josh Miller and John Whittington. A Paramount release.

Running time: 2:02