One behind-the-scenes tidbit that made waves a month before the new season’s release: the cost per episode. In a wide-ranging article detailing the streaming service’s financial decisions, The Wall Street Journal revealed each episode costs $30 million per episode. That beat out Game of Thrones, which up until then held the record for cost-per-ep with $15 million per episode for the final two seasons.

But with a year’s delay, feature-length episodes, and heavy CGI and makeup work, film-sized budgets aren’t that shocking. Altogether, Stranger Things 4 cost about $270 million, or a quarter of a billion dollars.

Stranger Things 4 is a globe-trotting story. The show has moved far beyond the reaches of Hawkins, with scenes set in California, Nevada, Utah, Alaska, and the USSR. But the actual filming locations are a bit different.

Hopper’s scenes occur in a former detainment camp, Lukiškės Prison, located in Lithuania. The production filmed most of the California crew’s road trip in and around Albuquerque. And as always, Hawkins is filmed around Atlanta, including the Creel House. The Norman Bates-esque house is the Claremont House and can be found in Rome, Georgia. The six-bedroom, seven-bath fixture dates back to the 1870s; it was a bed-and-breakfast before filming.

Back in 2015, when Stranger Things’ first season was filming, Millie Bobby Brown shaved her head to play her character. What a difference four seasons make. Due to her red carpet demands (not to mention roles in Godzilla, Enola Holmes, and the upcoming Damsel), Brown no longer has time to commit to El’s look quite so thoroughly. Her return to Hawkins Lab and the original buzzcut this season is all wigs.

One of the most anticipated cameos in Stranger Things 4 was Dacre Montgomery’s return as Billy, since the actor hinted he’d be back. But how he came back was intensely tragic — as a Vecna-created apparition in Max’s waking nightmares.

But even sadder: Montgomery and Sadie Sink never actually worked together for the scene. Due to Hollywood shutdowns, Montogmery filmed remotely from his native Australia, in Perth, while Sink filmed her part in the U.S., creating a “Rubik’s Cube puzzle” for director Shawn Levy to piece together, as he explained to Entertainment Weekly.

When the Stranger Things 4 trailer first dropped, everyone noticed all the new hairstyles. That’s not an accident; production wanted to make sure mid-1980s hairdos were boldly represented across the spectrum this season. The 1980s icons abound: Eddie Munson has the Ozzy Osborne, Chrissy’s hair is straight a la Olivia Newton-John in Grease, and her boyfriend Jason is wearing Tom Cruise’s Risky Business ‘do. Mike and Dustin are in the middle of grow-outs to recreate the MTV looks from the height of the hair metal craze. Iconically, Robin and Vickie have hairdos straight out of The Breakfast Club, with Robin as Ally Sheedy and Vickie as Molly Ringwald. (They’re obviously meant for each other.)

Of course, some main characters keep their iconic looks; for one, Steve’s hair is eternal. Others still reflect where the characters are in life — Eleven’s bad hair goes with her social outcast status, and Max’s childlike braids are indicative of her not moving on from last season.

You know who didn’t get new haircuts for Stranger Things 4? Jonathan and Will Byers.

Do you know who desperately wanted one? Noah Schnapp, who plays the latter. Speaking to Insider, Schnapp admitted he’d lobbied for Will to abandon the bowl cut that’s been a character staple since the first season. Apparently, he’s brought it up over and over since the first season, but the Duffers and the makeup and hair teams aren’t budging. “There’s one more season left, but they’re pretty loyal to that cut,” Schnapp said. “I think it is a true kind of ‘80s classic haircut. So I don’t think we’re gonna lose it anytime soon.

After Murray spent the first few episodes talking up his karate abilities, fans were prepared to watch him get his butt kicked when it was time for the fighting to go down. That he didn’t is a pleasant surprise for all involved.

In an interview with GQ, Brett Gelman, who plays Murray, revealed he’d trained for months ahead of time. “I took it very seriously. Murray is a black belt,” he explained. “I think that I trained more and requested to train more than they had originally anticipated that I’d want to. For three months — two months before the shutdown and then a month leading up to shooting — I was with these amazing trainers, Simon Rhee and Phillip Rhee, who are Taekwondo masters.”

After three seasons in which various CGI monsters, from Demogogans to the Mind Flayer, were Eleven’s main antagonists, Season 4 changed course. Season 4 features a real enemy and not a demon-like CGI figure that happens to be human-shaped. Although he’s initially called Vecna (after the Dungeons & Dragons demon), by season’s end, fans learn he’s human: Henry Creel, the long-lost son of Victor Creel. More importantly, he’s Number One, Brenner’s first patient, with whom Eleven shares DNA.

That means this season’s big bad is an actual person in makeup, not a CGI monster. Actor Jamie Campbell Bower plays both, and the Vecna version is him under tons of prosthetics and makeup, or as he put it, about “90%” him. He told Variety it takes seven-and-a-half hours to get suited up for his monster scenes, which he then films in for 12 hours, and then goes back to the chair, where it takes another hour to dismantle.

But it’s not wasted time — Bower uses the time in the makeup chair to get inside his character’s head and then the hour it takes to get cleaned up to help him power down.

The song that saves Max from Vecna is her favorite pop hit, Kate Bush’s seminal “Running Up That Hill (A Deal With God).” The track was Bush’s first single off her debut album, 1985’s Hounds of Love. The original release made it up to No. 3 on the U.K. Singles charts for 1985 but only made it as far as No. 30 on the U.S. Billboard Hot 100.

Stranger Things 4 rectified that injustice by putting the track front and center of the new season and playing it in multiple episodes, as Max goes around listening to it on constant repeat like her life depends on it. By the time the series had been out three days, the track had reached No. 1 on iTunes and Spotify. In response, Bush put out a rare statement, thanking Stranger Things and fans for making her song a hit once more.