When Ridley Scott was hired to directAlien, he was expected to phone in a haunted house movie set in space to cash in on the success ofStar Wars. But Scott went a few steps further and turnedAlieninto arguablythe pinnacle of the sci-fi horror subgenre. Thanks to the movie’s allegorical storytelling and H.R. Giger’s haunting otherworldly designs,Alienis hailed as a classic of sci-fi cinema. And thanks to Scott’s Hitchcockian command of tension, pitch-perfect pacing, and fiercely effective jump scares, it’s also one of the greatest horror movies ever made.

After Scott’s movie was praised as a masterpiece andbroke new ground for female action heroes, 20th Century Fox was eager to follow it up with a sequel and hired James Cameron to write a script. Cameron knew he couldn’t write a horror film that would be able to top Scott’s monumental achievement, so he changed course and made his sequel toAlien,Aliens, as an action movie.

Ripley and Newt in Aliens

RELATED:Sigourney Weaver Reveals Why ‘Aliens’ Was The Best Time Playing Ripley

Whereas the firstAlienmovie saw a single xenomorph picking off an unsuspecting space crew one by one, the second movie saw Ripley heading straight into a festering hive filled with dozens of xenomorphs and their gigantic queen. Cameron surrounded Ripley withgun-toting Colonial Marineswho could riddle the swarming aliens with machine gun fire to level the playing field a little. As soon as the Marines realize they’ve wandered into the aliens’ hive, they open fire and shoot their way out.

Ripley in the final battle of Aliens

But despite the presence of the Marines, this is still Ripley’s story, through and through. Once again, she’s one of the only survivors. And once again, she has to face the nefarious alien threat alone. After the aliens have abducted Newt, Ripley will stop at nothing to get her back – including going deep into the xenomorphs’ hive on her own and killing every alien in sight.

As withany action movie classic,Alienshas its fair share of explosions. When the dropship comes down to save Ripley and the Marines, the crew unexpectedly finds alien life on board and the dropship crashes to the planet’s surface in a giant ball of flames before it has a chance to save anyone.

Movies thatblend action and horrortend to veer one way or the other. For example, theResident Evilmovies are more interested in the action side than the horror side, whileOverlordhas a more overtly horror-oriented sensibility and its action goes out the window after the opening war scenes are out of the way. For all the mind-blowing action scenes inAliens, it’s never too far away from a big scare like Ripley’s chestburster nightmare or Ripley and Newt waking up to find themselves locked in a room with a facehugger to remind the audience that it’s primarily a horror film.

Ripley’s final confrontation with the xenomorph queen is one of the most awesome climactic brawls in the history of action cinema. In addition to havingthe perfect one-linerto get the queen’s attention (“Get away from her, you b*****!”), Ripley hops in an exoskeleton suit to make it a fair fight. This sequence is more than just a well-choreographed beat-‘em-up; it resolves the sequel’s themes of motherhood in a spectacular blaze of glory.

WhileAliensis often described as one of the greatest action movies ever made, Cameron didn’t leavethe first movie’s quintessential sci-fi horror traditionsbehind completely. Like its predecessor,Aliensis still a great sci-fi movie and a great horror movie. Cameron expertly continuedAlien’s rare blend of terror and thoughtfulness.Alienshas plenty of thought-provoking science fiction elements, like a greedy corporate suit trying to smuggle alien eggs back to Earth, and it also has just as many jaw-dropping jump scares as Scott’s original masterpiece, from the revelation of the swarm of xenomorphs in the vent to the alien rising up from under the water in the sewer behind Newt.

Cameron has been lauded as one of the masters of movie sequels, having helmed two of the most acclaimed sequels ever made –Aliens, of course, andTerminator 2: Judgment Day– and the method of switching genres to keep the story fresh is a common thread between both of them. While the firstTerminatormovie was an intimate, suspenseful tech-noir that occasionally veered into horror territory,T2is an all-out action extravaganzathat needed a record-breaking budget to accommodate its spectacular set-pieces. Just likeAliens,T2blows its predecessor out of the water with bigger, bolder action.

WhileAlienandAliensare both crossover hits praised as one of the greatest entries in more than one genre, all the subsequentAlienmovies have failed to even satisfy asAlienmovies. None of the following movies have come close to matching the greatness of the first two. Maybe the way forward is to incorporate different genres into the franchise, like a full-on war movie set on a battle-ravaged planet in theAlienuniverse or a space western in which a lone gunslinger encounters a bloodthirsty xenomorph.