Depending on how the trailer for The Purge plays for you, the following is going to be good or bad news: It's not exactly the movie the marketing is selling. Yes, it's about a futuristic alternate reality where one night a year all crime is legal, and it does indeed focus on one family whose house is being attacked by people wearing creepy masks, but the trailer makes it look more like a home-invasion movie along the lines of The Strangers than anything else. That's not entirely accurate. The reality is that The Purge has more in common with an unlikely source: the video game Bioshock. And that's a great thing.

No, James DeMonaco's film doesn't take place in an underwater city, nor does Ethan Hawke shoot bees out of his arms to protect his family (though that would be awesome). It does, however, call to mind the cult of Rapture at the heart of Bioshock. If you've never played the game, it takes place in a massive underwater city that an eccentric billionaire built as his own special utopia where everyone could get away from the evils that so often plagued their old lives. Things ran perfectly for a time, but an undercurrent of mania began to infect the city, and its citizens became addicted, reliant, and self-destructive when given a taste of the future (in this case, plasmids that let users alter their DNA and do incredible things).

The Purge takes place in a gated community full of plucky, smiling, picture-perfect citizens who are waiting for the one night of the year they get to perform their patriotic duty of purging all of the anger and hate and jealousy from their hearts. When the people in the masks show up at this rich family's doorstep demanding to get in, it's not the start of a home invasion in the traditional sense. It's the introduction of a moral dilemma: Do you use the supposed tools of utopia, as is expected of you, or do you do nothing? The family has to decide, and that's where the heart of The Purge lies. It's not The Strangers with a twist. It's a brutal Twilight Zone episode that paints this sci-fi-tinged scenario that, like the underwater city of Rapture, is utterly inconceivable in our real world but believable within the context of their world.

Having said all that, there are still home-invasion elements in The Purge. There's a whole lot of creeping around dark hallways and sneaking up on unexpected victims. There are people in masks who carry big, sharp blades. But the context for all that stuff is more important than the ingredients themselves. They exist to look good on the poster and cut together well in a trailer and get a few jolts out of people in the theater. The real meat of the movie isn't about who these people creeping into Ethan Hawke's massive, fancy house are; they introduce themselves right away. It's about the decisions everyone makes that night.

Without getting into spoiler territory, the key to unlocking what kind of vibe The Purge is going for lies with the very first death in the movie and how characters react to it. It's actually kind of hard to process, because we as audiences are attuned to think of any death in a horror movie as a shocking, game-changing occurrence. Here it's not, though. Characters are upset and affected by it, but zero blame enters into the equation, and that's kind of fascinating. It sets up this bizarro world where people truly do respect this murder-is-legal mindset. It's a very matter-of-fact moment and the atypical, emotionally detached reaction to it is strange at first, but eerily logical once you think about it.

The Purge isn't about "who are these people?" and "why is this happening?" It's about participation. And to that end, it's once again like Bioshock. Do you participate in what supposedly keeps the utopia running smoothly, or do you rail against the system? The choices that each character makes might surprise you, as will the movie overall. The fact that it isn't strictly a home-invasion movie -- but still has some of those factors -- may turn off pure horror hounds, but hopefully it doesn't mean the movie will be dismissed outright. It's not perfect, and it works in some elements that don't really bring anything new to the table (like the masks, which seem to exist just to freak audiences out, though I'd say the same thing about the similarly masked Splicers in Bioshock), but it's got a little more going on under the hood than you'd think just from reading the description or watching the trailer.

So, if you've written off The Purge as being just another home-invasion movie, give it a shot. If you were excited about another home-invasion movie, well, give it a shot, too. Point is, it's not as cut and dry as the trailer would have you believe. It's got weird ideas, memorable characters, a bleak sense of humor, and a new kind of utopia-as-dystopia story (hey, that's like Bioshock!). Even if those elements don't always sing in perfect harmony, at least they're there. At least it's not just another The Strangers.

Note: We're reposting this editorial on The Purge from late May to coincide with the film's release this weekend.