Take Cabin in the Woods, for example. That film began like any other horror movie, and followed Evil Dead's footsteps until completely destroying its own concept. You're Next reminds a lot of Cabin in the Woods, although this time You're Next takes home invasion movies and turns them on their heads. Adam Wingard has obviously done his research here, and the subgenre is well-represented throughout the first half of You're Next.
1) First, he introduces characters piecemeal, taking the time to give them their own scenes during the introductory phase of the film. We meet the parents, Paul (Rob Moran) and Aubrey (Barbara Crampton), as they get their vacation home ready for a family reunion with their kids. Then Crispin (AJ Bowen) and Erin (Sharni Vinson) arrive, somewhat hesitant to meet-and-greet with the relatives. This is numero uno on the list of home invasion contrivances - the audience must at least establish a connection with the victims, whether it be good (Crispin and Erin) or bad (brother Drake [Joe Swanberg] and his girlfriend).
2) The setting is explored but only vaguely. Wingard takes us through this vacation retreat in the opening, letting us see the layout. It's obvious these places are going to be used later, so the audience must realize they're there. It's sort of like Chekov's gun, except for area instead of props. The props come later.
3) A game is afoot. Home invasion movies are often elaborate; they're never as easy as using guns, and though that's probably a step away from realism, the audience understands this. The closest You're Next gets to guns is a crossbow; the rest of the items are blunt instruments meant to cause mass destruction.
At first, You're Next feels quite derivative. The first moments of the film are fairly deceptive, and the amount of screaming in the scenes of early violence can be hard to sit through, not because it's emotionally affecting but because the characters seem like caricatures. No one can do anything during the attack besides bicker and scream, and that's difficult to take from a film that must force its players into action.
Soon, though, it becomes apparent that this is exactly the point. Black humor is a big part of You're Next, from the dialogue to the violence, and the characters are sort of dumb because of this. In a way, they help to offset our main heroine Erin, and they also resemble some of us who might be frozen in fear instead of ready to jump at the chance to kill someone.
Once the secret's out about Erin, the title of the film flips meanings. "You're next" is not solely referring to the main characters, and the victims aren't necessarily who we think they are. Like the Evil Dead remake, You're Next ushers in a new era of seriously capable and brutal females; these are different final girls than we're used to, and they're a far cry from Barbra in Night of the Living Dead.
With that said, Simon Barrett's script is often not the deftest or most fine-tuned. There are moments that linger too long, dialogue that explicitly states what should be implied, and a final wrap-up that someone in the audience audibly sighed at. You're Next is a movie that's extremely fun, but it's one you can't think about too deeply. If you do, you lose the magic and the humor.
You're Next is the kind of horror movie that redefines the home invasion genre. Its aspirations are huge while its scope limited. The generic plot masks the real goal of the film: take what you've seen, turn it around on you, and do it over and over again. You're Next doesn't exactly keep you guessing, but you shouldn't be thinking about it anyway. Just let the events overtake you.