If memory serves (it's been awhile since I tried it), in Two Worlds you move with the WASD keys (the so-called First-Person Shooter style) and use the space bar for actions such as talking to NPCs and taking items. Mouse is used for fighting, Left-Clicks swing your weapon. Use number keys to activate feats (and whatnot) in your quickbar. That's all I remember off-hand, but note that I can remember this wrong. I'm sure if you search the mighty Net, you'll find a FAQ or something, that explains all the controls to you (plus you might be able to customize the controls though options menu or something).
As to the game itself, it never really inspired me much. I must confess that I only played it for a few hours, but never-the-less, during those few hours, the game did not interest or inspire me enough to continue playing. In adition, I didn't much like the combat mechanics (and there is a lot of combat). YMMV.
I've read a few positive comments about Two Worlds, though. Especially from those who liked the Gothic games, but I did not like it and I do like the Gothic games - go figure.
It is pitch black. You are likely to be eaten by a grue.