There’s an intriguing new video game adaptation to watch in theaters — and no, it’s not that one. Exit 8, based on the game of the same name, hits the big screen on April 10th, and it’s part of a burgeoning trend of horror movies directly inspired by indie games and liminal scares on YouTube. (See: the surprise success of Iron Lung and the upcoming Backrooms feature.) It’s also the rare adaptation where I’d highly recommend playing the game before seeing the movie. Doing so makes the surreal experience of the film into something even stranger, and the good news is playing the game is a very easy thing to do.

The game is a curious project to be adapted in the first place. (Also, for clarity: The game is called The Exit 8, while the movie is just Exit 8.) It has no cutscenes or story, and there are barely even any characters. Instead, it’s more about the setting. You play as a nameless figure trapped in a looping hallway in a Tokyo subway station, and the only way to escape is to follow a very strict set of rules, which involve spotting anomalies and turning back if something seems off. It’s extremely creepy, with posters that move and an unsettling businessman who seems unaware of your presence. And as you play the game, and scour your surroundings in search of anomalies, you’ll become intimately familiar with the hallway. After a playthrough I could tell you exactly how many lights are on the ceiling and what each poster on the wall looks like.

The film version adds a narrative over this skeleton of an idea, as you follow a young man who becomes trapped in the hallway and desperately tries to find a way out. You learn a little about what the loop actually means, and there are a handful of other characters trying to understand the place, which adds a different kind of tension. You even discover that the silent businessman has a backstory. But as an adaptation, one of the most remarkable things about Exit 8 is how vividly it evokes the game. The set is almost identical aside from a new addition (which factors into one of the movie’s most terrifying sequences), and the nameless protagonist has to follow the exact same set of rules as players of the game.

What this means is that if you still have the experience of playing The Exit 8 fresh in your mind, watching the movie becomes very trippy. The first time I watched Exit 8 I couldn’t help searching the walls and ceiling, looking for anomalies I’d seen in the game I had just played. It helped really immerse me in the setting. Watching the film was almost like watching a really elaborate let’s play — which was actually part of the intention. When I spoke to Exit 8 director Genki Kawamura last year, he told me that he spent a lot of time watching YouTube to see how people played the game, which in turn helped influence how various characters in the movie approach the mystery.

“Everyone is playing by the same rules and in the same space, but each player makes different mistakes, and they have different reactions to each failure,” he explained. “And I thought that because of that, the personality of the individual player comes to the surface.” He described his approach to adapting The Exit 8 as an attempt at creating “a new cinematic experience that blurs the lines between video game and cinema.”

The best way to appreciate what he’s going for is to play the game. Thankfully The Exit 8 is very accessible: It only costs a few bucks, is available on a huge range of platforms (including mobile), has very simple gameplay, and, provided you don’t get stuck, lasts about an hour. That’s a small price to pay to better enjoy one of the most interesting horror movies of the year.