LA Noire largely does away with the free-roaming that enhanced the appeal of Grand Theft Auto and Red Dead Redemption. As you drive around, you do occasionally hear of street crimes to which you can respond, and there are hidden vehicles and LA landmarks that completists can collect and visit, but the overwhelming focus is on the main story.
So it's a good job that, bucking the modern trend for short single-player games, LA Noire is satisfyingly meaty. Rockstar reckons it's roughly equivalent in length to two seasons of a TV series, a claim that feels roughly accurate.
Perhaps, then, it would be more accurate to argue that LA Noire more closely approximates a television show than a film – it beats any film hands down in terms of the sheer amount of entertainment on offer, which of course is an advantage games have always had over films.