In this tie-in, the starring characters aren't anyone from the movie, but rather a female mercenary and a futuristic insurance adjuster who are trying to locate the remains of the spaceship "Hunter-Gratzner," that crashed with Riddick (and more importantly, it turns out, a priceless collection of stolen artifacts) on a desert planet. The two begin to piece together what happened on the ship and on the planet, throwing in a little bit of back-story on the people who crashed there, including Riddick.
Although Diesel gets top billing, it's unclear whether he was actually involved at all. Riddick is never clearly seen (so it could be a stunt double) and all of his lines are taken from Pitch Black. And although there's finally a hint in the tie-in about what might REALLY have happened to the survivors of the crash, most of the build-up portrays the movie as something very different than it is, more of a "Friday the 13th In Space" than anything else, with Riddick possibly hunting down and axe-murdering the other survivors. People who chose to see (or NOT see) the film on the basis of that were completely misled. People who based their expectations of future Riddick films around the back-story he was given in this, sadly, were ALSO misled; virtually every detail has since been discarded for the overinflated universe of "The Chronicles of Riddick."
Technically, the tie-in is atmospheric and interesting. It's completely irrelevant, however, and an opportunity to make something with actual relevance was, sadly, squandered.