Warning: This article contains spoilers for Alien: Romulus.

Alien: Romulus director Fede Álvarez still remembers when he saw Terminator 2: Judgment Day for the first time because it gave him a whole new appreciation for gunfire.

“Every once in a while, film should put a new spin on things that makes you think, ‘Oh, now I’m looking at the real version of this,’” Álvarez tells Entertainment Weekly. “Until Terminator 2, there was a standard sound for gunshots that everybody used. Then James Cameron showed up. I still have a fresh memory of hearing that first Beretta that they shoot at the mall. Suddenly, it was this pop-pop, very high-end sound with no low-end. Watching that, I remember feeling that we’ve all seen guns being shot a million times, and even that can always be done better.”

Álvarez wanted to apply that same attitude to his new sci-fi sequel. Alien: Romulus has versions of familiar scenes you’ve seen before in previous films, but with the dial turned way up.

Want more movie news? Sign up for Entertainment Weekly's free newsletter to get the latest trailers, celebrity interviews, film reviews, and more.

20th Century Studios

Take the chestburster, for instance. The embryonic Xenomorph emerging violently from John Hurt’s chest in the original Alien is as iconic as anything in cinema, and some version of it has appeared in every franchise sequel or prequel since then.

Alien: Romulus, naturally, has a chestburster scene because viewers might ask for a refund without one. But Álvarez’s version has extra elements added on top of the central body horror. Instead of taking place at a dinner table, Alien: Romulus’ chestburster scene takes place in a space shuttle rapidly spiraling out of control and crashing into the massive space station that gives the film its title.

“We literally vibrated the set,” Álvarez says. “The whole cockpit was built on a massive gimbal. So, anytime there was a moment where the shuttle crashes against the station, the whole gimbal would shake. When the character falls, it’s super violent. We had to work with stunt doubles, obviously, to do it safely. During the whole birth and everything, all the shaking is real.”

Álvarez didn’t exclude himself from the action. “It was the best theme park ride,” he says. “We were all in it with them. I was with my monitor, trying to stay in place while people were shaking the hell out of that thing. It was awesome.”

20th Century Studios

The director promises “there’s not one frame of CGI” in the scene. It helped that he was working with experienced VFX technicians who had been part of the late Stan Winston’s team on Aliens and knew how to handle a practical Xenomorph.

“There were two versions of her,” Álvarez says of Navarro, the unfortunate character played by newcomer Aileen Wu. “One was Aileen actually standing up with a whole fake body attached to her to be able to puppeteer the creature through. That's how they did it in the original movie. And then there was another version of her, which was twice her size but didn't have a head, just a chin, to be able to push the chestburster through with more detail. It needed to be a little bit bigger to see more details, like its breeding valves and hands and all that. So, it was two different versions, but all optical visual effects were done on camera. I’m super proud of that.”

Álvarez also made a change to the end of the scene. In the original film, the little chestburster speedily scurries away after emerging from Hurt. But Álvarez didn’t think that would be a natural response from such a creature, so instead, the newly-born Xenomorph luxuriates on the chest of its dead human incubator, making the scene feel even more obscene.

“When babies are born, they’re exhausted,” Álvarez says. “So it would be this slow burn coming out of the body. I think it’s more gruesome and perverse, but also doesn’t betray reality. I approached it as if it was a nature documentary. The direction I gave the puppeteers was stuff like, ‘The baby looks for the scent of the mother now,’ and so it raises his head to do that. That just makes it way more realistic, and we applied that principle to everything in the Alien world.”

So it's cosmic body horror that feels like a rickety roller coaster and was filmed like the grossest nature documentary of all time, and that's just one scene in Alien: Romulus. The whole movie is in theaters now.