A couple things about this movie we have to get out of the way right off the bat:
1) Yes, the title is a line of dialogue from the movie, and no, it doesn't make any goddamn sense at all. The character who says it was never killed, so it's one of those bait-and-switch deals, like I Spit On Your Grave. But unlike that movie, where the main character surely would have spit on somebody's grave were there any actual graves in the movie for her to spit on, this movie's titular line of dialogue actually contradicts everything that the character who speaks it has been saying about herself for the whole running time. It's like they came up with a title first, but then forgot to tell it to the guy they hired to write the movie, but they'd already printed up the posters so they were stuck with it.
2) Lindsay Lohan does not get naked in this movie. But you already knew that, since she plays a stripper and strippers don't get naked in movies anymore, a dangerous precedent set by Jessica Alba in Sin City and continued by Rose McGowan in Planet Terror. (You know, I'm starting to think this is all Robert Rodriguez's fault.) Personally, if I were a stripper, I would be insulted by these Hollywood starlets who think they're too good to do what real strippers do every night for far less money. Spoiled brats like Alba and Lohan want all the cool accoutrements that come with playing a stripper (the "bad girl" attitude, the sexy dance routines, the slutty costumes, etc.) but they don't want to do any of the heavy lifting. It's like if an actor got cast to play a cop but refused to carry a gun. I understand your ethical dilemma, but that should have stopped you from taking the role in the first place. It's not a matter of me wanting to see some tits; it's a matter of an actress' lack of commitment to the role she has been paid to bring to life. And in the case of I Know Who Killed Me Even Though I'm Not Dead And It's Not Really Me I'm Talking About Anyway, it's even more insulting because all of the other strippers surrounding Lindsay Lohan get naked. It's like they needed some tits to create a realistic atmosphere for a strip club, but Lindsay's were too expensive so they had to hire some stunt knockers. It just ain't fair. These other actresses have dreams, too. They want to be famous and star in their own movies, but they don't have the full might of the Walt Disney Corporation backing their careers, so they have to pay their dues and show off some skin like many accomplished actresses did before they got famous. And for what? So Lindsay Lohan can have her stripper cake and eat it too. Fucking bullshit.
Okay, we should probably talk about the plot now. Lindsay plays a high school piano prodigy who gets kidnapped by a psycho. When she shows up later, she's missing a hand and a leg and claiming that she's really a stripper named Dakota. So since the movie tries real hard to make you think that she's just crazy, you know she's really telling the truth. That's the shocking twist, that everything turns out pretty much how you thought it would.
This movie has already become a little notorious, not only because it so closely mirrors Lindsay Lohan's real-life transformation from America's Sweetheart into America's Drunken Whore. It's also a completely ridiculous movie from beginning to end. This thing is positively Italian in its aggressive commitment to utter implausibility. It's like a Brian De Palma thriller, only half-assed. De Palma would go so far over the top that you'd have to appreciate the audaciousness of it all, but the best this movie can do is get you on a "so bad, it's good" level. But on that level, this shit works. It is pretty goddamn goodly bad/badly good in on nearly every category.
Let's break it down:
Cinematography: This is one of those movies with symbolic colors, so everything is either blue or red. Blue represents Good Lindsay, red represents Bad Lindsay. At one point, a character shows up wearing yellow and automatically becomes the most interesting thing in the movie. You can't take your eyes off of him. It's like that little girl in the red dress in Schindler's List. But what I don't get is why everything except Bad Lindsay (who always dresses in red) is blue. And I do mean everything. There is more blue in this movie than in a Jacque Cousteau documentary. Seriously, it's like the director has some grudge against the color blue. Maybe the Smurfs murdered his mom or something. The killer even wears bright blue gloves and a blue stocking over his face. An awesome twist would have been if he turned out to be in Blue Man Group and was chopping off limbs to create some kind of syncopated musical routine. That would have ruled.
Script: I love these movies where not only is the basic premise impossible to swallow, but they also throw in some other minor outlandishness for no good reason. Okay, I'm gonna have to spoil the big twist: Good Lindsay and Bad Lindsay are separated-at-birth twins, so when something bad happens to one of them, it happens to the other, too. So when GL gets her hand and leg amputated, BL's hand and leg just fall off. That's some pretty crazy shit to base a whole movie on, and any other movie would have tried to make everything else as realistic as possible to compensate. Not this one. This one also throws in a super-strong robotic hand that responds flawlessly to nerve impulses and a prosthetic leg that needs to be plugged in at night. It's shit like this that marks this movie as something special. Another thing that makes this movie particularly Italianesque is that the cops are fucking retards. In real life (as well as in better movies), what investigators do when hunting for serial killers is to cross reference the victims' histories to find points of comparison in hopes of discerning a pattern that will lead them to the perpetrator. They don't do that here. They just yell at Lindsay because she's not cooperating. If they'd done what I suggested, they would have easily found several clues linking the victims to the killer. (And in any case, they would have known it was him because he's the only guy in town who has dozens of prosthetic limbs hanging from the ceiling in his basement. Shit hanging from the ceiling = psycho.) As a film viewer, you'll actually figure it out in the first five minutes, since there's this one scene right at the beginning featuring a character who's only around long enough to get all intense about something that he doesn't have any business getting intense about. Then he never appears again, and the movie doesn't give you any other suspects. The only way the villain could have been any easier to identify is if he'd been played by Christopher Plummer.
Acting: Dude, it's awful, particularly from Ms. Lohan herself, who is utterly unbelievable as both a goodie two-shoes and a chain-smoking tramp. I, for one, am grateful. Competent acting could have easily raised this movie to the level of mediocrity, which is the last place you want it to be.
So yeah, if you like terrible movies, this is a terrible one you'll like. It's not as balls-crazy as The Wicker Man remake, though, because it doesn't have Nic Cage dressing up in a bear costume and beating up women. That's the kind of thing that only comes along once in a lifetime, though, so don't hold that against I Know Who Didn't Actually Kill The Person Who Isn't Technically Me.