This is the only review you should read.

Rating: 4/10 (2 May 2003)

Identity? Who is who or what(?!), not so much who is the killer. I will not give away any of this film or run pointlessly through every scene like other people who review movies on this site will do so read on...
You can say this movie is over-cliched with horror elements like other reviewers have stated, but it is quite intentional and that is the best part of this film. It's typical slasher setups and scenes are well designed for scares and/or suspense and you will find yourself engrossed in the first half of this film. The direction and well crafted scenes are good enough here to blend suspense and confusion into good entertainment.
To all those who claim this movie is only for "intelligent" viewers please don't write another review ever again. Scenes in the first half of this film may be standard to modern horror but because of the acting talent of most of it's stars, it comes off far better than many films of this genre. But when it comes time to blend all of this films confusion and mystery with a meaningful, satisfying resolution it falls flat. You may be surprised, but if you don't feel had, you weren't really paying attention. So all of you who claim this to be a highly intelligent psychological thriller, you apparently don't realize the writer of this was also responsible for Jack Frost and its sequel. It must have been about time for him to create the next thriller/surprise film and try to break into the money-making theatrical market.
James Mangold is not without talent and he tries terribly to make this bad script work and it may have, if only he treated it less seriously. The disorder you will see in Identity is turned cartoon-ish by Hollywood yet again here and if you are a Psychology major like one reviewer here claimed, you shouldn't be thrilled by this film but insulted. It's only there for the surprise not coherency. We don't actually know anything about the surprise character either, so when the story turns down a different road it doesn't really work and destroys everything there was good about the movie (unless of course your mind is too locked in "WOW - I - AM - SUR-PRISED" mode). The other plot twist is predictable if you are used to "who-dun-it horror" and ridiculous as well in flashback scenes shown near the film's climax.
Cusak turns in an expected good performance here. Liotta plays another defiant/angry character as he usually does these days but still remains beleiveable and the remaining members of the cast do a good job as well except...
Amanda Peet is not a great actress. Please don't base your review on whether someone is cute or not - it's insulting to those who know and appreciate good filmmaking. Go watch Blind Date. She should stick to bad comedies because when she acts out any real emotions in this film it's usually unintentionally funny. Nevertheless she wasn't as terrible as I expected she would be. Pruitt Taylor Vince was clearly miscast but since his character was poorly underwritten as well it didn't matter. His performance was barely acceptable.
Identity is not a total waste. In fact, it is an improvement over many recent horror outings of the past few months (if I mentioned any of them I'd be too scared someone would respond that they were actually good) though it could be skipped without loss just as well. See it merely to be entertained, but don't think about it too long to the point of delusion or you'll make it into a masterpiece (like others here have) which it clearly is not. ** out of ****.