LOS ANGELES – “It’s nice to just show the movie and say, ‘Here it is, hope you like it,'” Jason Reitman said to me at a party following a “pop-up” screening of his latest film “Young Adult” last night. And he’s been doing just that, in select cities across the country — Chicago, San Francisco, Minneapolis, Austin and a stop north of the border in Toronto — aiming at the kinds of fans who’ll line up for a secret screening without knowing what the film will be. And the experience seems to have invigorated him a bit.

Going into these cities, he and screenwriter Diablo Cody haven’t done the usual press commitments. No chatting with local news stations, radio shows, newspapers and college papers like you’d expect. In and out and a “hope you like it.” It’s fair to say the kind of intense press rounds he exhausted on “Up in the Air” two years ago were the last thing he wanted to do this time around, but it’s also been about setting a foundation that says, “This ain’t ‘Juno.'”

And no, “Young Adult” is not “Juno.” Not that the latter is the trifle it’s come to be considered since its 2007 release (it has its dark and emotional moments), but the latest Cody/Reitman collaboration is an unflinching piece of work committed to following its lead character on a downward path, eschewing a narrative of redemption and never conceding any ground.

It’s the film Reitman says he wanted to make, the film he’s proud he was able to make, and he took a chance in saddling up to it. He had written an adaptation of Joyce Maynard’s novel “Labor Day” and was all set for it to be his next film while Paramount was seeking out directors for Cody’s script. Suddenly, though, the opportunity was there for Reitman to take a crack at it, and so he took a leap, put “Labor Day” on hold and set out to make an uncompromising dark comedy within the studio system.

And it is certainly that. These are light spoilers, but in a post-screening Q&A at the New Beverly Theater, Patton Oswalt — who is fantastic in the film and delivers a performance you might not expect out of him — noted that it’s a reminder of films like “The Conversation” or “Five Easy Pieces” (the sort that often screen at the New Bev), which were dedicated to further embedding characters into who they were at the start of the film, rather than offering a traditional Hollywood yarn with lessons learned and a dramatic arc.

“I am of the mind that assholes don’t change,” Cody said in the Q&A. “And also, people in general don’t necessarily change in the dramatic way we see them change in the third act of movies.” She then gave credit to Reitman for fighting for the integrity of that aspect of the film. (End of light spoilers.)

All of that will surely make for a catchy talking point along the press tour, but I actually think it’s overly simplifying things. “Young Adult” is ultimately a rather twisted tale of finding one’s inner worth and caring about yourself enough to move forward, and that, I think, is a significant thing for a person to learn.

Oswalt, meanwhile, has a whole theory on it being a horror film of sorts, but that’s another story for another day. For now, suffice it to say “Young Adult” is quite possibly Reitman’s most refined outing to date, his voice becoming clearer, his thematic interests taking further shape. It’s a brutally dark comedy but it is a very adult piece of work, playing in hues all the more uncomfortable for how true they really are on a primal level.

Charlize Theron gives a stellar, bitchy, biting, layered, at times moving performance. Oswalt commented to me and my colleague Drew McWeeny at the after party that he thinks this will be, more than “Monster,” the performance people will think of when they see her from here on out. And I actually think that may be the case. Unlike that film, for which she won the Oscar in 2003, Theron is exposed here, playing a vicious personality with no makeup to hide behind. It’s a quality piece of work that should bring her another Oscar nomination.

Oswalt, meanwhile, is so touching and funny and more than the mere comic relief you’d expect from the trailer. He gets a few key dramatic moments to sing and he really sticks the landing on each of them. I’ve had him chalked up for a Best Supporting Actor nomination for weeks upon weeks based merely on the early word, and I’m happy to see that vetted out after last night’s screening. If he really puts in the work, he can easily find himself in that mix. He’s so lovable on the mic and will no doubt bring the house down in Q&A after Q&A as he did last night.

Finally, also of note for one key scene is Collette Wolfe, who knocks a moment toward the end of the film right out of the park. And it’s that scene, Reitman says, that made him want to make the movie. That scene IS the movie. But I’ll say no more.

From here, the film comes off its mini-tour and enters the traditional press arena. I’m not sure how critics will respond. I kind of anticipate a great many will knock it for its lack of redemptive tissue, but I think savvy audiences will spark to its inner, dark truths. We’ll see how it plays out. But you can certainly understand why Paramount and Reitman have been particular about letting the cat out of the bag in a specific way. This is not a paradigm-fitting piece of work. Nor was it ever intended to be.

“Young Adult” opens in limited release Friday, December 9 and expands further on December 16.