In “Y2K,” director Kyle Mooney recreates December 31, 1999 with such a specific but deliberately broad brush that it recalls the vision of the 1950s in “Back to the Future.” A specific moment in time, simultaneously captured and reduced in such a manner to sell the younger folks on the setting while making the older folks do the “Leonardo DiCaprio finger point meme” every five seconds. Millennials may wince once they realize the era of their childhood has now become period piece fodder, their entire childhood now an alien enough world to require very specific production design, but it’ll only happen after they’ve giggled in recognition and appreciation. Mooney’s film assumes its target audience was alive and aware at the turn of the century, and gears its best jokes accordingly.

But “Y2K” is only a period piece raunch comedy about two dorky teens trying to get laid (or at least score a kiss) by midnight for so long before it becomes … something else entirely. Plot details were specifically kept out of the picture ahead of the movie’s premiere at the SXSW Film Festival, and while I imagine any amount of marketing will reveal the film’s basic premise, it’s shame that most folks won’t be able to watch this movie like its first audience did — potentially unaware of the big genre shift the film takes surprisingly deep into its running time, as every “worst case scenario” envisioned by those concerned about the Y2K bug back in the day turns out to have not been worst case scenario enough.

Yes, this is an “end of the world as we know it” movie, but I’ll leave it there. If distributor A24’s marketing department decides to take it further, take it up with them.

Evan Winter’s script is built around those familiar teen tropes: one shy high school dork (Jaeden Martell) and his outrageous best friend (Julian Dennison) decide to reinvent themselves on New Year’s Eve and hit up the big party where every clique has gathered to drink, dance, and ring in the millennium. The hot, cool girl (Rachel Zegler) will be there, of course. Maybe she actually likes the shy kid? Then midnight strikes, that above-mentioned shift happens, and the characters find their world … altered. Let’s just say the movie earns its R-rating.

Mooney, a first time filmmaker best known for his bizarre and outrageous work on “Saturday Night Live,” is most at home when “Y2K” is a collection of gags and genre pastiches. Clearly a nerd who knows his audience, he leans heavily on the aesthetics of the period, rightfully recognizing that certain costume choices, musical needle drops, and shots of AOL dial-up screens will receive hoots and hollers from viewers his age. And he’s right. Call it nostalgia, but the exacting recreation of 1999 is extremely novel and entertaining in 2024. He’s also the kind of nerd who knows that people who cheer those gags will appreciate practical VFX, stop-motion animation, and primitive computer generated imagery that recalls the bleached eyeballs visuals of “The Lawnmower Man.” As a director of clear good taste, he also knows the value of a ridiculous computer hacking montage.

When Mooney is in joke mode, sprinting from gag to gag without room to breathe, “Y2K” is a great time at the movies: a midnight movie in the truest sense of the word. Its capacity to spiral from one tone to another recalls absurd experiments like Adult Swim’s “Too Many Cooks,” where the audacity is kind of the whole point. The film suffers when it slows down and tries to become, for lack of a better term, a “real movie,” attempting to give flesh and substance to characters and concepts who had previously functioned as vehicles on which to place ridiculous jokes. Zegler, Dennison, and Martell are capable actors, but they’re essentially props in Mooney’s milieu, not proper characters. “Y2K” showcases occasional ambitions of wanting to be “Shaun of Dead,” but it’s incapable of achieving Edgar Wright’s specific blend of parody and pathos. It’s too detached, too ironic, too interested in slicing off the treacle and letting it bleed out on the road.

And that’s fine. Kyle Mooney doesn’t need to be Edgar Wright. He just needs to be Kyle Mooney. The film’s very specific sense of humor will probably repel as many folks as it attracts, but that’s the point of a movie like this — either it feels like it was made for you or it doesn’t. Like many comedies that have garnered a passionate following, Mooney seems mostly interested in making himself laugh, in indulging himself with gags that celebrate imagery from a very specific moment in time. A third act cameo, one that I still can’t believe they managed to pull off, sums up the movie’s very specific reason for existing: even when the late ’90s were garbage, it was our garbage. Let us celebrate our failures as much as our successes. And party like it’s 1999.

/Film Rating: 7 out of 10