Alternate Character Interpretation: Every single one of the characters at the motel becomes subject to this following the revelation during the final act of the film: they're all the split personalities of a man suffering from Dissociative Identity Disorder.
Captain Obvious Reveal: The reveal that Robert is not Malcolm Rivers had some viewers quickly figuring out that the main story took place in Rivers' Mental World way before the movie uncovers the twist since Conservation of Detail meant that Rivers was an important character despite never interacting with the other characters, not to mention that the first scene hinted at Rivers' multiple personalities.
Creepy Awesome: After discovering why everyone is trapped at the motel, Ed becomes this. He speaks in a soft whisper, loses all traces of emotion, and calmly walks forward to kill Rhodes even after Rhodes has already started shooting him.
The film also features a stand-out performance from John Hawkes as Larry, who starts off as an untrustworthy Smug Snake and Jerkass but ends up being a surprisingly nuanced character with a very human backstory.
Adaptation. includes a plotline where a character conceives of a mystery movie where everyone is just a personality of a single character, and it's implied to be a terrible idea.
During the big montage at the end, there's a rather hilarious shot of Timmy doing an Unflinching Walk with a Psychotic Smirk on his face as the car explodes behind him and a storm rages all around. It's like they were trying as hard as they could to make a meme that would go viral.
"Whores don't get a second chance!"
Narm Charm: Jake Busey hamming it up as the creepy prisoner. "Come on, man, you can tell me. I'm good at keeping secrets. I've got a whopper myself!"
Paranoia Fuel: You're trapped in the middle of nowhere during a freak storm, surrounded by mysterious strangers, and people start dying in increasingly violent ways. What if the killer is some escaped lunatic? What if it's the person standing right next to you? What if the killer is you, and you don't even know it?
The image of a baseball bat shoved down Robert Maine's throat.
Don't also forget the fact that after Caroline was killed, her head was put into the washing machine and her body wasn't found. EEP!
Special Effects Failure: Rhodes stabs the cop, who supposedly looses control of the car as he dies, but you can easily see the supposedly dead cop expertly steer the car into the skid.
