FAQ for
The Chronicles of Riddick (2004) More at IMDbPro »

To gross more at the box office, the film was heavily cut in order to obtain the financially lucrative PG-13 rating. This version was released in theatres and later on DVD. Some time later, an Unrated Director's Cut found its way on the home entertainment market. It includes all the scenes that had to be cut out and adds more story to the film. It runs more than 14 minutes longer.

A detailed comparison between both versions can be found here.