- Alternate Character Interpretation:
- Is Jennifer genuinely as ditzy as she appears, or is she playing it up?
- Does Jennifer only kill Colin and Chip just to take what Needy has, as she has done throughout much of their friendship, or does she do it out of having repressed romantic feelings for her friend?
- Awesome Moments:
- ""St. Jude, patron saint of hopeless causes, please give me the power to crush this bitch."
- Needy finally calling Jennifer on her shit during the fight at the pool.
- Crosses the Line Twice: Jennifer is bound with ropes in preparation for a human sacrifice. The lead singer of Low Shoulder, having invoked a demon, raises the knife... and the whole band breaks out singing "867-5309/Jenny" over her screams.
- Director Displacement: Some people wrongly assume that Diablo Cody directed the film, when in reality she only wrote the screenplay. It was actually directed by Karyn Kusama.
- Ear Worm: By the end, you will hate Low Shoulder's "Through the Trees" just as much as Needy does, just from sheer catchiness alone.
- Ensemble Darkhorse: Out of all the characters, Needy.
- Evil Is Sexy: Erm, yeah. Though it's hard to find Jennifer sexy when she's in full evil mode.
- Fan-Preferred Couple: Most of the film's fandom ships Jennifer/Needy. Other ships are basically nonexistent. (Though Chip mostly manages to dodge Die for Our Ship.)
- Heartwarming Moments:
Needy: I love you.
- One before all the horror starts. While watching Low Shoulder's concert, Jennifer reaches for Needy's hand, squeezes it tight, and smiles. Self-centered Alpha Bitch that she may be, she does seem to genuinely love her best friend.
- After the fire, a jock is seen sobbing his eyes out in the middle of class after the teacher talks about how many people the school lost. A scrawnier, nerdier boy puts an arm around him, trying to comfort him. It's a surprisingly sincere, non-judgmental moment.
- The day after the fire, Colin tracks Needy down specifically to tell her he's glad she made it out alright.
- Chip gently suggesting Needy talk to the school psychiatrist. He's not trying to judge her or invalidate her emotions; he's sincerely worried about his girlfriend and wants to make sure she's okay.
- Chip's dying moments, while heartbreaking, are still quite touching in how he manages to Face Death with Dignity, and tries to comfort Needy. And then this:
Chip: I love you, too. (Tearful Smile) And you look totally hot in that dress.
Needy: You're clearly delirious.
Chip: No, I'm not.
- Hilarious in Hindsight: Needy has an Evil Dead t-shirt and has a poster of the first film hanging in her room. Cut to 2011 and Diablo Cody was hired to doctor the script for the remake.note
- Hollywood Homely: Amanda Seyfried as the "plain jane" Needy. However, the narration outright states that when they go out, Needy dresses herself down so as to not steal any of the spotlight from Jennifer, and is specifically forbidden from showing any cleavage, since Needy's is more substantial than Jennifer's. This means that, in-universe, the characters are entirely (if tacitly) aware of Needy's actual hotness.
- Also Jennifer. If she doesn't feed on schedule, she starts getting ugly... meaning "still Megan Fox but with heaps of makeup to give her shadows and sallow skin." Very likely intentional, as Needy describes this as being "ugly for her", to show how high Jennifer's standards are. Also, considering that her hair starts to fall out when she hasn't fed in a while, one could assume that she'd eventually end up looking even worse if she went a very long time without feeding...
- Hype Backlash: A substantial one had already built up against the film months before it was even released, mostly from people who thought Diablo Cody's work on Juno was massively overrated. It didn't help that at around the time of the movie's release, Megan Fox made some rather ill-advised comments about Michael Bay in an interview, further intensifying the backlash from those who thought Fox herself was overrated in various different ways.
- Jerkass Woobie: Jennifer. It is implied there is more than she's letting it on, allowing her general jerkassness run her life. Also her getting brutally murdered is another factor, especially since she's genuinely terrified when it's happening. She's also shown on the verge of tears towards the end when her hair starts falling out due to having not fed in a long time.
- Les Yay / Foe Yay: Jennifer and Needy's friendship is absolutely dripping in it. The bedroom scene takes it way past subtext. If you were under the impression that the trailer exaggerated it, it didn't, it actually toned it down.
- Come to think of it, the girl who told Needy that she's "totally lesbigay" in the opening had her eyes practically glued to Needy just before dropping the bomb on her.
- Memetic Badass: Chip. He survived getting eaten long enough to get to dry land, impale Jennifer, and even calm his girlfriend down over his own death. If he were the star, the movie'd be over earlier.
- Except, of course, that he acts blatantly stupid beforehand - Arbitrary Skepticism, walking on his own through the dark when there's a serial killer on the loose, instantly believing Jennifer's story about Needy and letting Jennifer lead him to an abandoned swimming pool, A.K.A. the ideal murder location. Needy may not be the brightest character either, but at least she isn't Too Dumb to Live.
- Nausea Fuel: Jennifer's attempts to eat the roast chicken are less than successful. And very messy.
- Jennifer finishes feeding on Colin by reaching into his torn-open belly and slurping up his blood from her cupped hands.
- One-Scene Wonder: Gabrielle Rose as Colin's mother, who gives one hell of a "The Reason You Suck" Speech to a couple of angsty Goths.
- Protection from Editors: Depending on who you listen to, Diablo Cody either had this directly from managing to parlay her success with Juno into getting a "no-rewrites" clause for this film, or indirectly as a result of the 2008 WGA strike meaning there wasn't enough time for another writer to come in and fine-tune the screenplay.
- The Woobie: Poor, poor Needy. She witnesses the deaths of lots of people in a fire, her best friend is abducted, murdered and brought back as a demonic being, and several of her schoolmates are brutally murdered by said best friend, including her devoted boyfriend. Then, to top it all off, she kills Jennifer and gets incarcerated for her murder. Also, following the ending, she's likely going to be spending the rest of her life on the run or in hiding from the authorities.