Enforced Method Acting: Lydia Mackay comments that in her role as Shion, she had to place an unlit cigarette between her lips in order to realistically portray Shion speaking with a cigarette in her mouth.
I Knew It: Not too surprisingly, considering the show's excellent use of clever foreshadowing.
Kougami used to be an Inspector.
Also Shogo being immune to the Sibyl System.
Masaoka being Ginoza's dad. Due to the mention of Ginoza's father being a latent criminal combined with Masaoka's age and fatherly air, many fans guessed it episodes before it was revealed.