While the gravedigger is probably one of the better characters to be in a module in a long time, my favorite encounter is with the mage transformed into a worg. A voice calling out from behind a tree stating "Please do not attack me, my appearance may disturb you" just sparks the imagination like no other way. I would enjoy if the transformed wizard could offer tangible help like a helpful clue, potion, or something if befriended but info is valuable too. 4th edition got rid of detect evil and I only allow "Sense Motive" to get a general sense that an NPC is "hiding something" so the worg/wizard works great for me.
There are some great scenes created from Tim Hitchcock's imagination that jump from the pages: One room is filled two feet deep with loose re-animated eyeballs and combined with a gibbering mouther. I would hate to walk through that room stepping on eyeballs.
There is a severed undead head in a magic cage that enables the head to speak. It is a dwarf who figured out all the traps in the tomb. That is a completely awesome idea! I plan on having him know about all the traps and layout of the dungeon but be very angry at being trapped in his cage and not helpful at all unless the party is extremely diplomatic. This is exactly the sort of stuff that is in the module that holds so much potential but the module doesn't tell you how to use it, that part is up to you. It's great, but for novices and DM's that lack creativity it might have been easier for the author to give more character traits to those NPC's. I think it's awesome that the party has a good chance to carry around an angry dwarf head that knows all the secrets of the dungeon but might be unwilling to help them and complains alot.
The main villain has an ability to be able to see and speak through all of his minions. This allows for a constant dialogue of threats, taunts etc between the villain and the party. I absolutely love love love this, I haven't seen any other adventures where you get to dialog with the main villain the entire adventure. Again it's personal style how a DM wants to use that but the power is mentioned once and not told explicitly to a DM to take advantage of it. Maybe paizo should write a "How to be a good DM guide"
My only criticism is that while the adventure does put forth a short backstory on the main evil guy, it could use more. I added a small story of an evil lich who lived 800 years ago and had an obsession with eyes because his eyesight was failing. He abducted people from town and ripped out their eyes and performed experiments to craft himself new eyes. This is the evil force that the knights put a stop to and made the tomb to entrap. I let the players uncover this eloquent story with a knowledge history check. I like how history checks let you flesh out the story and characters even more. Even if they failed the check they might be able to read it in the library of the adventure. I would add something like that to improve this adventure.