Hm, sorry, seems to be about Two Worlds II already …

It was a competition : http://www.twoworlds2.com/cd/competition-en.html

You must first click on "demo download", and then scroll down and then on "accept" - an then on one of the buttons to download it …

Strange … I had thought it was a browser game, but now I see that my memory had stored it incorrectly …