When a policeman's family is kidnapped by a sadistic crimelord he must kill a rival crime boss to save his family.

Oh, I forgot to mention: very lean!
But here's my slight tweak:

When his family is kidnapped by a sadistic crimelord, a by-the-book policeman must kill a rival crime boss to save them.

Strong sense of genre. Cool goal. And high stakes! But the main character's a bit bland. He needs a flaw. Also, something to consider: maybe not a cop? It might be too easy for a cop. Could we make him a librarian? A data analyst? Making it hard for the hero spices up the story. (Although it might mess with the sense of genre!)

I also like Steven's idea about the MC being the rival crime lord's brother, or having specialist knowledge. It gives the antagonist a believable motive.

Patrockable (Judge)

Big motiational hole here: Why does a crime lord need a cop to do a 'hit' for him? Doesn't he have goons of his own to do that? The mere fact that he is sadistic is not a strong enough a reason for him to waste time setting up a cop (who does not appear to be special in any way) to kill someone.

More is needed here to hook interest. For example, is the cop the rival crime lord's brother, or even son? (That would work well with the sadism trait.) Or is the cop an ex CIA or infiltration expert? (Which suddenly makes sense why the cop has been chosen over the regular goons.)

Steven Fernandez (Judge)