This is a gripping 2-1/2 hour movie, and worth it to pay extra for the IMAX experience. You'll need to pay attention, though, and don't leave for a restroom or popcorn break, or you'll get lost. But the last hour and a half leaves you breathless - the guy beside me was literally on the edge of his seat for the last hour!
The plot was deep and twisted, but yet had very few inconsistencies or unanswered questions.
Casting was fantastic - acting was great! It was the best overall movie experience my husband and I have had in the past 5 years.