Grade: 2.5/5.0

“Deadpool” was released in 2016, a year in which the limits of the superhero genre were tested. Our favorite crime fighters glumly yelled about their moms. Director David Ayer yelled “fuck Marvel” at the premiere of “Suicide Squad.” “X-Men: Apocalypse” dared to ask “Oscar Isaac, but he’s blue?”

It was bedlam.

But then came “Deadpool,” delivering an antihero ready to lampoon it all, raking in critical plaudits and box-office bucks alike. Two years later, “Deadpool 2” doesn’t clear the bar set by its predecessor — it runs right smack into it, colliding with an inglorious thud that won’t be heard over chuckles at the film’s admittedly effective gags.

The best one involves the film’s very premise — to protect a young mutant named Firefist (Julian Dennison) from the time-traveling warrior Cable (Josh Brolin), Deadpool (Ryan Reynolds) assembles a menagerie of mutant misfits, which he immediately dubs “X-Force.” Yes, Deadpool knows the name is a little derivative, and no, you won’t see the resultant, gut-busting bait-and-switch coming.

When it does come, it’s so darkly amusing that one forgets how similar “Deadpool 2” is to its predecessor. Screenwriters Rhett Reese, Paul Wernick and Ryan Reynolds shamelessly play the same tune, hoping that reupholstering familiar beats will suffice. It doesn’t. For all of its determination to replicate the original’s success — down to repeating jokes themselves — the script quickly and clumsily sidelines the first film’s standouts.

“Deadpool 2” largely ignores super-sidekick Negasonic Teenage Warhead (Brianna Hildebrand) and her new, electric chain-wielding girlfriend (Shioli Kutsuna). Most egregiously, the film makes no space for Deadpool’s fiancée Vanessa (Morena Baccarin) — denying her character the growth she deserves through a frustratingly backward narrative move. She has less to do than Peter (Rob Delaney), an X-Force recruit possessing only the power to be a punchline.

For all the characters that it underutilizes, the film would’ve done well to exclude deadpan bartender Weasel, played by T.J. Miller, who was accused of sexual assault last year. Though producer Lauren Shuler Donner said the film was too far into post-production to replace Miller with another actor, an easy, true-to-form fix would have been to let Deadpool break the fourth wall and call out Miller’s behavior himself.

But to the film’s credit, its new characters are its greatest strength. As Domino, a mutant with luck on her side, Zazie Beetz brings the wry comedic chops that made her a standout on “Atlanta.” Likewise, as the vengeful, aptly named Firefist, Julian Dennison proves once again that he’s one of today’s best young actors, maneuvering between comedy and tragedy with the deftness of a performer twice his age.

As for Josh Brolin’s performance as the Terminator-esque Cable, the actor behind Thanos proves that his gravelly lower register won’t get old anytime soon. He wears a smoldering scowl like a glove — or perhaps, a gauntlet. With Brolin also starring in the upcoming “Sicario: Day of the Soldado,” Hollywood’s current favorite grump just might retain his monopoly on melancholy through a summer three-peat.

While the new additions to “Deadpool 2” never fail to please, they can’t assuage a disappointing turn by helmer David Leitch, who cut his teeth as a second-unit director before crafting some of the best set pieces in recent memory with films such as “John Wick” and “Atomic Blonde.”

Known for gloriously long takes that render each punch exponentially more painful, Leitch seems to be in cruise control for “Deadpool 2,” largely foregoing the showy oners that put him on the map in favor of painfully vanilla skirmishes. Virtuosic moments peek through, and the film’s action is much sleeker than anything previous director Tim Miller mustered — yet we expect more from Leitch than mere competence.

With the future of “Deadpool 3” uncertain, though an X-Force film is likely full steam ahead, perhaps it’s better to heed the words of Deadpool himself and “stop at 2.” Stick around for a mid-credits scene that’s as obligatory as it is wholly dangerous for the integrity of the “X-Men” franchise. But then again, the series has a knack for shooting itself in the foot.

“Deadpool 2” opens at UA Berkeley 7 on Thursday.