The investigations are becoming longer as and moves forward in the game, and a good fifteen grand minimum of hours to finish the game unlikely to be too much - twenty hours on average I would say - unless you want rusher through the game without resolving minor offenses regularly occurring in the City of Angels (aborted robberies, family disputes ending tragically, inquiries ...), look for the cars to collect, etc.
And pay attention to the actions and reactions! Driving at breakneck speed in the city, destroying everything and crushing pedestrians will drop drastically the degree of success of the ongoing investigation; and if you misinterpret facial expressions of suspects during interrogation, or witnesses, it will possibly cost indices can be valuable to successfully complete a deal ... which case your boss will make you feel your incompetence (it's lived)!
An excellent game, which I will put a very slight downside: like good old Assassin's Creed first name (which I personally liked despite everything, I said), I must admit that the same pattern is repeated after investigation Survey: harvest index, go to a point X to question a witness, apprehend a suspect, question the suspect ...
But the story is told well enough to not be off-putting, and are slipped each time with pleasure his costume LAPD Inspector to conduct a new investigation.
Surely a game not to be missed if you love the detective genre, and 40s.
That said, clearly a game not to put all hands in view of the crimes that take place and certain themes (rape, pedophilia ...) ...