Pitch Black was the original movie. Chronicles of Riddick was the sequel.

I would highly recommend Pitch Black if you're in the mood for it. It's a combination Alien meets Asimov's "Nightfall" scifi thriller/horror. Nothing too original, lots taken from other sources, but the characters and their interactions are interesting and it kept me interest all the way though the end. The main character, Riddick, is very interesting in an "I'm a badass" kind of way. He's a classic villlain with a streak of humanity.

Enter the sequel: "Chronicles of Riddick"
I wasn't expecting much, and I got much less. This was AWFUL! One of the worst movies I've ever seen! Talk about a bunch of ideas that are all crammed in the same movie with none of them going anywhere. It couldn't decide if it was fantasy, or science fiction, or both, and wound up splattered between all of those. All this movie suceeded in doing was ruining a good character, Riddick. This movie should be destroyed.