This 'thriller' started-off slowly, and at one point I briefly considered ejecting the DVD, not helped by Jim Carrey's performance. For, even though he's had non-comedic roles before, it was hard to forget that I was watching a usually-whacky comedy star desperately trying to tone things down, so much so that I couldn't really buy into his character.
In this particular serious role, Carrey was simply boring, his almost noir-style voiceover being so contrived that it became annoying. And it wasn't just because we, as viewers, are used to the higher-pitched, over-enthusiastic, silly behaviour that marks out his comedies. Indeed, if this was Carrey's usual acting persona he wouldn't get any work, because it was dull and totally uncharismatic; not because the character demanded that, but because he was trying too hard to play against type, portray seriousness and feign confusion/ schizophrenia.
Anyway, about the actual plot, things shift up a notch when the lead becomes interested in the subject of a book randomly bought for him by his wife. Time goes by and he becomes increasingly obsessed with the number 23, but things only really get going towards the end when you get a 'twist', something many reviewers apparently saw coming (but I'm glad to say that I didn't). Still, I was hoping for one *final* twist at the end, one where perhaps his son got killed trying to save him or something. Instead, we get a "happy ending" (of sorts), which doesn't really fit the style of the film.
That said, the use of the word 'happy' in relation to this film is contradictory, because it's dark, depressing, weird and a bit too arty for its own good to be perfectly frank. Not a terrible film, but be warned that you may get bored and/ or confused. And although there's some tension, I can't imagine that you'll feel thrilled by the end of it. The Number 23 is a renter at best.