Yeah, the critics liked Pitch Black more, and it is indeed really good. But CoR has a whole universe of mythology behind it. It's Vin Diesel's home brew setting for D&D and of course featuring his main player character Riddick, a rogue. It just places you in that mythos without explaining it, but you can then guess at and wonder about those things. There's lore that was well developed in Vin's head for the Necromonger religion, the Elementals, the Furyans, the Mercs, Helion Prime (planet that's invaded), Crematoria (prison world), etc.