For the uninitiated, it originates from a game back in '01, and had a sequel in '04. It was, quite literally, the first of its kind. Heck, even The Matrix game wasn't quite the first to come up with bullet time in games, it was Max Payne. Great and all, but the main draw for the game, in my opinion, was the awesome storyline and characters.
It's got really dark, gritty feel to it. You've got nothing to lose, your wife and baby daughter got murdered, you have nothing to your name, you're just an undercover cop who's got on the wrong ends of both the law and the underworld.
In the middle of all of this, a romance develops with some assassin hire to kill you, (cliche I know, but it's the way the story is told.) and stuff just develops from there.
It's really a great nod to film noir of the old, only in the form of a video game. For the guys who haven't played it, please do. For the movie-goers, this is one film you're gonna have to catch. The storylines are unrelated, but they do use the characters, and that's good enough for me.