[2'09"] It's always worth even revisiting locations you've previously explored as there are lots of quests to discover later in the game.

This is something I've really enjoyed having recently played Risen, G1, and now currently G2.

More often than not, many times it's worth returning to places you've already covered as things change. NPCs frequently will have dialog recognizing quests you've progressed and solved - oftentimes even giving a little extra experience beyond the experience you get completing the quest itself. It is a nice touch and makes their games and endless search for Easter Eggs.