they're all playing characters from their other movies
I mean the way they're acting, their mannerisms , even the actual characters:
Spacey is pretty similar to Jack Vincennes in that he's lost his way/corrupted and has to relearn his humanity through the events
Moore is totally playing Meredith Johnson (even the same clothes)
Irons is abit like Simon Gruber in that slightly insane leader
Quinto is pretty much his version of Spock
assume Simon Baker is abit like The Mentalist
Betanny & Tucci are basically the same characters they always play