There are so many ways that Unfriended could have gone wrong. Ahead of the film’s 2015 release, it was reasonable to predict that Leo Gabriadze’s micro-budget slasher flick would do little with its central gimmick, offering nothing more than a lazy series of repackaged found footage cliches and a cringe-worthy misunderstanding of technology to boot. But it unexpectedly became one of the most ingenious horror films of that year. Unfriended is dripping with creativity, and it still holds up remarkably well. Primarily, that’s because Gabriadze, along with writer and producer Nelson Greaves, was able to masterfully tap into how we actually use computers to communicate, taking full advantage of the format to deliver a bounty of fresh and imaginative scares.

Neither of those was a given, especially not the film’s depiction of technology. After so many years of watching fictional characters video chatting using fake programs that broadcast all of the footage in full HD with minimal lag, audiences had more or less grown to accept that computers in movies just don’t look or feel anything like they do in real life. But right from the start of Unfriended, we buy into the fact that we’re watching an actual teenager use a real MacBook. Blaire’s desktop is cluttered with an unorganized collection of pictures; she has Tumblr, the Forever 21 online store, and an episode of Teen Wolf loaded up in a row of tabs; and she bounces back and forth between Messages, Skype, and Google Chrome at a speed that’s neither too fast nor too slow.

When Blaire types, she doesn’t get the thought across immediately, either. She frequently misspells words and has to correct herself, and she rethinks what she wants to say all the time, something characters in movies rarely do. Early on, when Mitch jokingly suggests on Messages that the mysterious person in their Skype chat could be a ghost, Blaire first types, “STOP!!!” But she deletes that, instead choosing to send, “Ya probably.” In another scene, when Blaire is talking to Laura, she first types, “Who’s doing this. It’s super messed up.” But she edits this to just, “Who’s doing this?” When Mitch asks about Laura’s past, Blaire begins typing “When we were kids…” and then, “Her uncle….” Finally, she changes it to, “Family stuff, it doesn’t matter.” By contrasting what Blaire was thinking with what she chooses to say, Gabriadze finds an innovative way to get inside his main character’s head and comment on how we all use computers to project a highly controlled image of ourselves. If Unfriended was a movie taking place outside of a desktop, none of this would be possible.

Anyone who has ever participated in a Skype conference with a group of friends will find the one in the film to be quite accurate as well. The teenagers just sort of casually hang out in the opening minutes, and the call is often chaotic, with everyone talking over one another constantly. There’s almost no way you’re going to catch all of the dialogue, and that’s a good thing, as too often conversations that play out over video chat in films just don’t feel natural. Crucially, everyone’s video is webcam quality rather than movie quality, and it’s always glitching and lagging. The glitches themselves look fairly genuine too, as opposed to the fake kind we often see in movies that are meant to represent the idea of webcam glitches but where they’re obviously being manufactured in an editing program.

All of this authenticity is no small feat, especially considering the actors were not even actually using Skype while shooting the film and the glitches are obviously being manufactured here too. This, combined with the fact that the movie plays out in real time and isn’t noticeably chopped up in the editing room, means we’re lulled into the security that comes with relaxing alongside friends on a Skype conference, and we don’t necessarily feel like we’re watching a Hollywood production.

Compare all of this to a movie like The Den, an extremely similar film that came out shortly before Unfriended. It follows a woman, Liz, who uses a Chatroulette-esque program to talk with strangers from around the world as part of a study. But it’s not Chatroulette; it’s a fictional creation called The Den that doesn’t have an exact real-world analog, since it both connects you with random strangers but also connects you with your friends and lets you message or video chat them like Skype or FaceTime.

Liz’s use of her computer is a lot less believable than Blaire’s. We see almost nothing on it that isn’t directly related to the plot, for one, and in some scenes, she types at a ridiculous speed as if the movie is just trying to hurry her along. Plus, nearly every conversation seems rehearsed, with none of the clumsiness that characterizes the partially improvised dialogue of Unfriended. That doesn’t mean The Den is a bad film, but it means that its world just isn’t as inherently relatable as Unfriended’s, and that’s important when a lot of the horror of these movies comes from subtle disruptions in the status quo. In Unfriended, the world is so darn convincing that something as simple as seeing the forward button missing in Gmail manages to be unsettling.

To be fair, there are a couple of elements of Unfriended that break the illusion. If you want to pause and nitpick, you can spot inconsistencies, including a bit of editing in the teenagers’ video feeds. But this isn’t something that you really notice unless you’re consciously looking for it. What is noticeable is the fact that Gabriadze fades out the Skype conference audio at times, mostly when Blaire is doing something important in another window like talking to Mitch on Messages. But the decision to do so was understandable, as otherwise, the audience might be confused about what they’re supposed to be paying attention to. Overall, what matters is that fundamentally, we feel like we’re watching people use computers as actual human beings do. In Unfriended, we always do, and in movies like The Den, we often don’t.

It’s not that Unfriended is great just because its use of computers is realistic, although it was certainly a thrill to see an underrepresented side of life put up on screen in a major way. What’s much more important than just checking off realism boxes is the fact that Gabriadze’s portrayal of technology being so spot on means he is able to build scares around aspects of the computer world that we’re all intimately familiar with but that have never really been exploited in a horror movie before.

Take, for instance, the film’s absolute best scene. Val calls into the Skype conference, but her video isn’t moving at all. Instantly, we all recognize this problem: the video has frozen. Strategically, the movie established earlier that Val has a dog, and now, the dog barks in the background to confirm our suspicions that her audio is working but her video isn’t. This is a common issue on Skype that virtually every audience member has likely dealt with before. But then her phone vibrates into frame, and it’s revealed that her video isn’t frozen; Val herself is frozen in real life.

There’s obviously nothing revolutionary about creeping us out by showing us a possessed person remaining perfectly still. But in Unfriended, Gabriadze combines this trope with the incredibly specific modern phenomenon of a person’s Skype video being frozen while their audio still works, and by doing so, he gives an age-old scare new life. Had the movie based itself around a more glamorized version of the video chatting experience, this inspired scare couldn’t happen.

That’s just one example of Gabriadze using our knowledge of technology to freak us out in novel ways, but moments like that are constant throughout the film. Early on, a Skype call popping up on screen serves as a jump scare. In another scene, a computer alarm reminding Blaire that she has a test tomorrow startles us as well. Before several of the deaths, the video slowly buffers in a realistic fashion in order to build up dread. At one point, we’re on the edge of our seats watching the spinning pinwheel. Later, the movie even incorporates Spotify to bring us some dark comedy; after it has been revealed that Blaire has been lying to her boyfriend, the song “How You Lie Lie Lie” begins playing.

Gabriadze also utilizes the fact that his film is set on a computer screen in order to communicate a lot nonverbally. Right from the opening scene, he gets across almost everything we need to know about Laura’s death by having Blaire visit a series of web pages, first LiveLeak and then YouTube. An exposition dump taking place via a LiveLeak description is, once again, a pretty innovative method for getting that information across, and the result is that the teenagers don’t need to have an awkward conversation in which they reiterate something they all already know just so that we can hear it.

The same is true when we see Laura’s obituary and can read about the fact that she was a special education student and had attempted suicide once before, two key pieces of backstory that are never said out loud. In that same vein, Gabriadze also has fun with some macabre visuals that are just thrown up on screen but that nobody comments on. This includes an ad encouraging Blaire to “ESCAPE,” and another that asks, “Who’s following me?”, both of which are darkly appropriate. Later, a camgirl ad pops up with footage of Blaire taken from earlier in the film, although she never points this out herself.

Compare the way this movie really dives deep into the many facets of the computer world to The Den. Not to pick on a solid found footage movie, but in that film, director Zachary Donohue really strays from the central hook in the last half. Near the end, for instance, Liz fights back against an attacker, and Donohue cuts back and forth between three separate cameras rather than staying confined to one as he had at the start. Later, he slaps a camera on the protagonist’s head so that she can walk around the area where she’s being held, and the movie essentially becomes Megan Is Missing, having not as much to do with webcams anymore. It’s as if Donohue is trying to break free of the constraints that come with the gimmick he has chosen whereas, in contrast, Gabriadze gleefully celebrates those constraints with Unfriended and happens upon a goldmine of computer-based scares that The Den didn’t fully get into. There are so many movies from throughout horror history with an interesting hook where the director never fully capitalizes on all of the potential, but Unfriended certainly isn’t one of them.

Indeed, other than the final five seconds, Unfriended never leaves the computer, and the last act is constructed around the question of how to make characters sitting and talking to one another on Skype suspenseful. The answer is a game of Never Have I Ever, during which our hearts beat faster and faster every time we hear the sound of the Skype message notification. The movie even uses our inability to see anything in the characters’ rooms other than what’s in front of the webcam to make for a tense sequence in which Blaire and Adam both have notes printed out, but they can’t reveal them or else the other person will die. This simple but effective finale is totally in keeping with the spirit of the film, and once again, it wouldn’t work at all if this was being shot like a normal horror movie, or even a normal found footage movie.

Really, there’s little that doesn’t work about Unfriended with one notable exception: the ending. All throughout, the movie had served as a cautionary tale about cyberbullying, and in the last couple of minutes, it seems to be gearing up to a thought-provoking conclusion. Blaire is revealed to have filmed the embarrassing video of Laura that led to her suicide, and she has to deal with a flood of vile comments, the exact fate that she doomed Laura too. Well, actually, she only has to deal with those comments for about a minute, as Laura immediately kills her rather than forcing her to live with the consequences of her actions. We get the sense that things only went down this way so that the film could have “one last scare” where the monster lunges at the camera, but it would have been nice if a movie so one-of-a-kind didn’t have literally the exact same ending as Paranormal Activity and countless other found footage films.

Still, that’s not enough to ruin a movie that gets so much else right. What Unfriended ultimately understands so well is that if you’re going to center a horror film around a gimmick, such as it taking place entirely on a computer screen, you should fully embrace that gimmick and think through all of the creative scares that can come with its limitations. This is something the best found footage movies do; think the audio from one camera playing over video from another camera in The Blair Witch Project, the night vision in REC, the fast-forwarding in Paranormal Activity, and the tracking in V/H/S. Although we’ve seen a handful of horror films built around computers, with Unfriended, Gabriadze and Greaves were the first to fully realize that the old found footage tropes shouldn’t just be squeezed into this new subgenre of horror. Rather, they recognized that they had a new toolset at their disposal, especially if they committed to keeping the computer world grounded in reality. Let’s hope director Stephen Susco can build upon that in the sequel, Dark Web, because in its own little way, the original movie is brilliant.