Well I don't know for the books, really. I didn't feel compeled by the games, though. Especially the first. I may do the second one of those days... Still, I don't know. I felt it was pretty common 'dark and mature themes'. Issues I had the feeling were second-hand issues, mostly because the game does a good job at making them commonplace, while in truth they should be very important topic. Racism, most notably. Come to think of it, I don't know what was 'mature' in what the Witcher was dealing with appart from the omnipresent racism / race superiority complex the human race has over the 'lesser race' like Dwarves and Elves.
I have the feeling that the "Black Company", as a work of heroic-fantasy, was much more pertinent when dealing with the horrors of things. Maybe Games of Thrones, but I didn't read it nor did I watched the show...
You don't know anything about The Witcher 2 then. I'd suggest sitting down and watching a walkthrough and you will see why it's a "mature" game.
Nah, I didn't play Witcher 2 more than past the prison break at the very beginning. Part of the problem is that i don't like the gameplay at all. It's hard to force yourself to play a game in whoch you don't even like moving the character

I did most of the first game, though, and never felt dragged into the story. Also hated the gameplay even more... But that's another topic.
What I mean is that, why put useless nudity in a game, especially when it seems to slow down the pace of the story and switch the focus? They'd bettter go all the way in, if the story is self-sufficient in term of mature topics. Racism, treason, death, [censored], whatever the story is telling, the nudity in Witcher 2 was not consolidating the plot.
Anyway even if I feel it was important to replace what should be 'advlt' or so-called 'mature' themes in video games to explain why I saw nudity as mostly pointless, I think I may have wandered off-topic with the Witcher and cie.
