I'm a bit stuck at the level of the catacombs where you must open all the outer tombs in order to open the 4 central tombs. I checked an IGN walkthrough about this which wasn't all that much help. I have opened ALL the tombs on this level and now I'm wondering where I need to go to descend to the next level. Top? Bottom? Somewhere obvious? It can be hard to make out details in this game. I wouldn't be surprised if I had just walked by a staircase that opened up after dealing with the tombs...

**SPOILER**

Go to the center of the area where there are two tombs together (3B see image), hold the mouse pointer over one of the two central tombs to reveal a passage to below. .. =)

IMHO, this is the best DD walkthru.

Thank you. Wanted to come back and delete my original post because I had found it and yeah... it was fairly obvious. haha

You're welcome . . . =)