Realism? I didn't know phone operators in '47 had access to googlemaps and a vehicle registration database to look up partial license plates cross referenced with car makes in a couple of seconds.
Not very realistic either that you can't repeat questions during an interrogation. Interrogating is about asking the same questions over and over again for hours trying to find cracks in the story. Not ask one question, decide and move on whatever.
Not very realistic that you can open fire on street crime all the time. An achievement for shooting a 1000 criminals? For headshots? Plus I was hit in the chest by a bullet, then still managed to sprint after the crook scaling walls and running up stairs, jumping from roof to roof, then shoot him while he got a hostage as they always seem to do in the end.
But who cares about realism it's a great game, and it's fun to play. The atmosphere is unbelievable, especially when you use the built-in black and white mode. After playing in black and white I don't want to go back to color anymore in this game. It looks exactly like those old movies from the forties.
However I wouldn't mind a realistc big budget crime scene detective game, based on the first 48 for example. As long as it's not like that god awful csi adventure game.