Question: Why was that one guy walking around with a knife in his back? Were some of the other Necromongers that way too?
Question: What exactly is the purpose of the inoculation-scar looking thing on the Necromongers neck, if it doesn't keep Vaako and his wife from plotting overthrow of the Lord Marshall, or help suss out the existence of the other remaining Furian?
Chosen answer: They say it in the film, it is one pain that helps to ease another. It is like an initiation and a branding all in one. It is the Mark of the Necromonger.
Question: On the planet crematorium it is 700 degree Fahrenheit in the light and -300 degree Fahrenheit in the dark. There is some kind of atmosphere with at least oxygen for people (they swap air). And there are volcanoes blowing CO2 in that atmosphere. Why does the temperature change that much with a atmosphere like that?
Answer: It wouldn't, this is a very good example of extremely bad science. For the temperature to change like that there would have to be no atmosphere, never mind a breathable one.
Question: When Riddick is in cryostasis on his way to Mecca, he has a vision of a Furyan woman telling him about the 'crime' that has happened in Furya. She proceeds to walk towards Riddick and we get a panoramic view of thousands, or perhaps millions of tombstones, presumably or rather obviously, of Furyans. The question is: Who went to Furya and buried all those dead Furyans? Who bothered to bury each one and put a tombstone on each dead body? Did Furya's neighboring planet send an expedition to Furya so they could bury the entire population of Furya? Kind of pointless, don't you think? Did they bring with them all those tombstones or were they just quarried from a nearby mine?
Answer: Because is a vision, I believe that the tombstones were added just to state the obvious about Furyans, that they are dead.
Question: Did that animal in Crematoria's prison (during the "feeding") have his eyes change (start glowing) after his contact with Riddick? I thought maybe I had missed something, but it looked like he/it had eyes like Riddick's after.
Chosen answer: The animals appear to be somewhere between a minor-class mimic of their surroundings and emotionally-triggered chameleons. As a sympathetic gesture towards Riddicks' dominant nature, it may have been altered purposely, or it was the animals' native eye color, when unstressed.
Question: Is Riddick's trick with the knife when the Lord Marshal first shows it to him physically possible? I can't tell if it's just CG or simply a very talented hand at work.
Answer: Completely CGI, and in my opinion, pretty bad CGI too. There's no way you can flip a knife underneath your hand they way that he did. Also, the entire scene is pretty herky-jerky, a good tip-off that it's CGI.
Answer: In the novelization they say that Irgun received the wound but because the knife was so near the spine it would require major surgery to remove it. He opted to leave it in.