Even though I prefer Bonehoard by an inch, I think Return to the Cathedral is the best example of stealth being possible with supernatural elements. It's way more focused than The Haunted Cathedral mission, and way less platforming heavy than the Bonehoard (even though I personally like that one more). The Haunts are easiest to deal with through sneak-attacking. If you don't do that, they are a big threat. Sitting in the dark, waiting for a Haunt to pass by, and hoping you can take it down from behind before another shows up, is thrilling. This is elevated further by the incredible atmosphere this level provides. It really focuses on the horror/terror factor, whereas Bonehoard had a tad more of a mysterious feel to it.

The "fetch quest" Brother Murus takes you on, is no different from regular objectives in Thief. This means it's great fun to fulfill the requirements the Hammerite spirit expects of you. You have to traverse different parts of the cathedral complex to accomplish your goals. One of them is filled to the brim with zombies, another has you do a little forging, and yet another has you ascend a long staircase to a cozy little observatory. The variety is there, despite the dark and oppressive nature of this level.

The only flaw is that the explosive you use to break open the door at the end, doesn't work half of the time. It's kind of dumb. Aside from that, this mission is one of Thief's best.