Just finished the game for the first time. I bought it years ago, but only recently got around to figuring out the problem with the unsigned drivers so the darn thing would play.
Overall, I loved it (with some criticisms I'm sure you've all heard before), but I got totally stuck in the tunnels in Chapter 5. I hate using walkthroughs, but when I get so fed up it's just not fun anymore, I do. However, even after reading several, I had no choice but to revert to an older saved game and start the area over.
Here's where I got stuck, after getting to the lower level and finding the gate with the symbols I said to myself, "Ah, so that's what position I have to turn all of those dials on the statues to." Only problem was, I wandered around the area for ages and couldn't find a way back to the upper level to change the statues I had already passed. All the walkthroughs I found simply told you what position to put those statues in the first time you find them, but without a walkthrough, you couldn't possibly know that! I'm finding it very hard to believe that a game like this would have a puzzle that is unsolvable without walkthrough, and/or reverting to an earlier point after getting information later in the game. So if that's not the case, what did I miss? How could I have gotten back to that upper level?