I bought the game and downloaded the english version of the game because I didn`t want a cut/censored version. First it seemed as if I had made the right choice. In the menu of the game there was a setting named "gore" witch I switched to "on", or better yet the default was "on", so I diddn`t have to do anything.
But as I played, I noticed that there is no single drop of blood in the whole game, only in the videos there is a little bit. WTF?
Can somebody help me, or tell me if I do something wrong?!?

It should be uncensored. The gore mostly comes from harmonic combinations. If you successfully clock someone with a support style, a green circle will appear around the opponent's legs. Pick a style that can complete an harmonic combination and hit the enemy with its power attack. Gore, there you go ;-)
Harmonic combinations don't work with all enemies, though. Further gore comes from finishing blows with weapons, e.g. by cutting off the opponent's head.

http://www.ign.com/faqs/2005/jade-empire-harmonic-combo-faq-607820
I have to add If you do Ice Shard Power (RMB) and then e.g. White Demon Power (RMB), it looks like there is no gore because the "shattering" everybody's talking about does not take place, the body just has a lie down and then vanishes.
WHEREAS when you do Storm Dragon Area (Both Mouse Buttons) and e.g. White Demon Power (RMB), you think you are playing Mortal Kombat.
Just saying.
And yes, this was the same enemy and not the ones who only fight "non lethal".