If you want to understand modern Hollywood and how it’s evolved over the last 30 years, all you need to do is look at the contrast between 1984’s The Terminator and 2015’s Terminator Genisys.

James Cameron’s Terminator was a quirky little sci-fi horror movie; an exploitation film, really. Alan Taylor’s Terminator Genisys is a glossy, enormous blockbuster. Cameron’s movie was rated R for intense violence and terrifying imagery; Taylor’s is rated PG-13 for bloodless action (because that’s the best way to attract the widest and youngest possible audience). Outside of a couple of glimpses of the future, The Terminator featured a single killer robot. Terminator Genisys, in keeping with our “more is more” times, boasts at least four cybernetic main characters (including two different Arnold Schwarzeneggers) plus dozens of other bots in the background. The Terminator told a complete story; Genisys leaves more threads dangling than a ratty old sweater (supposedly it’s the first installment in a new T-rilogy). The Terminator was a bold, original vision in an almost literal sense; the first T-800 design came to Cameron in a fever dream. On the other hand, there is nothing bold or original about Terminator Genisys, which is both a sequel and a reboot.

The only returning actor is Schwarzenegger, whose Terminator, now gray and weathered, says throughout that he’s “old, not obsolete.” The movie aims to prove the same is true for the Terminator series by revitalizing this moribund property with a new cast and special effects. The story opens in the ruins of Los Angeles circa 2029, depicting heretofore unseen events just prior to the start of the first Terminator. In the waning days of an apocalyptic war with a self-aware computer called Skynet, human resistance leader John Connor (Jason Clarke) sends his right-hand man Kyle Reese (Jai Courtney) back in time to protect his mother Sarah (Emilia Clarke) from a Terminator (a young Arnold Schwarzenegger, played by a nifty CGI creation).

When Kyle first arrives in 1984, Genisys looks like a straightforward reboot. Scene after scene recreates beats from the first movie; the T-800 stealing clothes from a bunch of punks by the Griffith Observatory or Kyle arriving in an alley next to a bewildered drunk. But suddenly, things diverge from their expected path. An older Schwarzenegger Terminator intercepts the young one; a liquid metal T-1000 (Lee Byung-hun) chases Kyle into a sporting goods store. And the Sarah that Kyle was told to expect by her son — young, innocent, scared — is nowhere to be found. In her place is a resourceful, determined warrior, more akin to the Sarah from Terminator 2.

So what the hell happened? The most frustrating part about Terminator Genisys is that the movie never answers that question. There are hints of an explanation in the actions of a mysterious new character played by Doctor Who’s Matt Smith, but even after Genisys winds its way through 125 minutes of explosions, chases, and shootouts it never comes close to solving the riddle of its alternate timeline. The heroes are too busy with their latest attempt to destroy Skynet to slow down and think about the ramifications of this inexplicable new scenario.

The film does a good job of keeping things moving — the pacing could have been inspired by the relentless T-1000 — and screenwriters Laeta Kalogridis and Patrick Lussier cleverly play with (and occasionally mess with) fans’ expectations through callbacks and homages. Genisys plays like the greatest hits of The Terminator, cherry-picking everyone’s favorite bits and pieces from the first two movies and finding a way to toss them together into one frenetic action flick. Afterwards, though, you may find yourself mulling over the loads of loose ends left untied.

Clarke and Courtney won’t make anyone forget Linda Hamilton and Michael Biehn, but they’re both solid as Sarah Connor and Kyle Reese. Still, the star here, in just about every sense of the word, is Schwarzenegger. If there is anything genuine in Terminator Genisys it’s his performance and its emotional core.

Even though it’s supposedly a dispassionate hunk of metal and fake skin, the Terminator has evolved from remorseless and unstoppable killing machine to aging superhero. Sarah Connor calls this Terminator “Pops” because it rescued her at a young age and raised her to be a soldier, which makes him yet another post-governorship Schwarzenegger role in which the star plays a struggling single father. (Arnold actually gets to fight his younger self at one point, about as powerful an image as one can imagine to summarize a man who’s spent the last few years dealing with the fallout of his terrible past decisions.) Genisys also continues Schwarzenegger’s ongoing exploration of the connection between masculinity and mortality (“Old, not obsolete” is a fascinating shift from Terminator 3: Rise of the Machines, where Schwarzenegger’s Terminator unambiguously stated “I’m an obsolete design.”).

Nothing in Genisys comes close to the poignance of Terminator 2, but Schwarzenegger does get to make a truly outstanding dick joke so it’s definitely not a total loss. In fact, “not a total loss” is probably a good way to describe Terminator Genisys overall. It’s fun and doesn’t take itself too seriously, and the setpieces are strong. Still, there’s something just a little bit dispiriting about it. It’s marginally successful on its own terms, but its terms are so much less ambitious and interesting than those of the old Terminators. By design, it’s just an okay copy of two great movies.

There’s a lot of talk in the film about how Terminators are “infiltration units,” designed to sneak into human communities and wipe them out from within. In that sense Terminator Genisys is kind of a Terminator itself; it infiltrates the franchise’s past, tiptoes through its established continuity, and then eradicates the version of history (and future) viewers know and replaces it with something new. It mimics the form of those old movies, but can’t replicate their soul. For thirty years, The Terminator franchise has chronicled an endless war between man and machine. As entertaining as Terminator Genisys is at times, it’s hard not to look at it, and at the American film industry in general, and wonder if the machines have already won.

Additional Thoughts:

-Terminator Genisys would make a very good double feature with Maggie, Schwarzenegger’s other 2015 film. Both movies are about fathers trying (and sometimes failing) to shield their daughters from the dangers of the world.

-As suspected, Terminator Genisys is a “selective sequel” that not only ignores the events of Terminator 3: Rise of the Machines and Terminator Salvation, but actively writes those movies out of continuity completely. Sorry Sam Worthington!

-If you haven’t seen the trailers for this movie, avoid them. They spoil one of the coolest twists. That’s something this Terminator has in common with the old ones; T2’s trailers spoiled the surprise that Schwarzenegger had flipped from villain to hero.