Okay, I don't really like doing `spoilers' in my reviews, but, in the case of `Riddick' I really can't help it. If you don't know, Riddick is the titular character who first appeared in the low budget sci-fi flick `Pitch Black.' That movie was such a success that it spawned a big-budget sequel `The Chronicles of Riddick,' which, for some reason, didn't seem to do so well.
The problem with the third instalment is... (and here come the spoilers) that it's approximately 1 hour 53 minutes long. The first thirty minutes consist of Riddick, alone on a barren world, fighting one computer-generated monster after the next. Hardly much story there. Then we see two separate spaceship descend on the planet, containing two lots of bounty hunters. And, for practically an hour, we barely see Riddick. Instead, the film turns into some sort of sci0fi `slasher' film where Riddick stalks and eliminates these baddies one by one. Only, we know it's Riddick killing these people and we don't really care anyway as they're all pretty much horrible people. It's only in the last half hour do things pick up (I won't spoil it any more by saying how). It's fair to say that I enjoyed the last half an hour, but it seemed like I had to wait an awful long time before I go to a bit that I really liked.
Basically, this is just `Pitch Black' again, but with different characters and a different setting. If you really enjoy the Riddick universe then you should like this. I enjoyed it really, however, I was hoping it would be better (or just different) to how it turned out. That said, if ever `Riddick 4' is made, I'll be there to watch it, too.
This is a generous 4/5 stars. I'm tempted to say it deserved more of a 3.5.