And here's my feedback on the latest update:
General:
* Page numbering - nice to see them - but having them down at the bottom centered would make them more obvious
* Synopsis - this is more of a DMsGuild sales pitch than a synopsis. Provide a brief outline of each scene so the reader can get the big picture in their head before diving into the details. (The final scene with the mummy was a surprise!)
* Have you done the encounter math to determine whether the 3rd Level PCs have the resources to accomplish this adventure in a single adventuring day? The number of possible encounters (involving damage to PCs) seems way beyond the 6-8 recommendation? And for the traps you should indicate their danger level to the DM. If you've not read the UA article Traps Revisited you probably should (given how trap heavy this adventure is
)
https://media.wizards.com/2017/dnd/downloads/0227_UATraps.pdf
* Dimensions of rooms. I find it helpful if the text of the adventure gives the brief dimensions of a room in the catacombs so I don't have to count squares on the maps. For example "Area A: The Sarcophagi. This first third of the long main hall..." OK so now I've got to do math too
* Highlight the Treasure as a separate item at each location. Sometimes it's buried in the Trap description.
* Really think this adventure needs some read aloud text boxes to describe each chamber. You're often using flavor text when the DM needs to know the reality of the situation.
Specific:
* Krillo, I agree with other posters that having this be a goblin is strange as they're generally considered evil monsters in most campaigns. Easy enough to substitute of course, but it's a head scratching choice right from the get-go
* In Krillo's Quest it seems Krillo is wanting to hire a group of thieves (the PCs) to raid the tomb before a different set of thieves gets there first?!
Not saying it's wrong, just a bit ironic.
Possible rewrite of your backstory for Krillo, perhaps he approached this other group of thieves first and their demands were too high and Krillo foolishly gave too many details away in the negotiations. Now he's worried they're going to take everything for themselves and won't the "honorable" PCs help him avoid this calamity for some lovely gold? It kind of ties it all a bit more tightly together?
Scene 1:
* Is the church door locked or at least closed? You've not specified. The church itself has no description at all. A little bit of atmospherics would be a nice bit of transition narration. "You make it inside the church and suddenly silence (and darkness) surrounds you. As you eyes adjust to the gloom you see a large open room with columns supporting the ceiling and an altar at the far end. In the center of the floor a large flagstone has been removed revealing stairs the lead down into deeper darkness."
Scene 2
* Provide some narrative text to describe the scene as the PCs reach the bottom of the stairway?
* There's no description of the stairways leading up and down from here. How do they look to the PCs?
* Area A
** 1) is the DM supposed to provide the runes on the sarcophagi to the players here?
** 2) You're not giving the DM any help on how to guide the players into opening the sarcophagi? The adventure is not supposed to be a puzzle for the DM too
At least tell the DM how they are sealed and whether they can be opened without damage.
* Area B
** 1) It would seem to me that the dirt would have dimples (or at least little rings) that would be visible to a keen observer hinting at something pushing through?
** 2) That dirt is super sensitive! Surely a little bit of pressure would be needed to trigger the spikes? Or is it a magic trap?
** 3) The warped wall seems a bit of a gotcha? PCs can try and overcome balance issues surely?
* Area C
** 1) When you say twist to you mean rotate? Does it operate kind of like an iris in a camera?
** 2) Not exactly sure of the mechanics of this door. You rotate it to change the words in the sentence but also to open it?
* Area L1
** 1) Again you're confusing description with information the DM needs. Is the large pot actually fastened to the ground? It can a "appear" to be fastened to the PCs but the DM needs to know the real situation in case the players want to mess with it.
** 2) I might also have some slime or something dripping down from the ceiling where the water comes in. there's no way that could have remained water tight for a 1000 years
Perhaps the room seems kind of clammy and damp (with an unpleasant odor)
* Area L2
** 1) This one seems a bit brutal - no reward here just pain? The clay jars are calling out to be explored and yield nothing. How about some potions of healing? (The PCs might need that by now
)
* Area R1:
** 1) Should be a statue of a male dwarf? "Man" makes me think human?
** 2) The kind of damage should be clarified. I'm thinking slashing damage for razors?
** 3) Where are the message runes located?
** 4) Not sure why the sections of the room are called upper and lower? it's all on the same level?
* Area R2)
** Lockbox 7) WotC does this also and it really bugs me. A potion of poison indistinguishable from a potion of healing is a gotcha. So how can the players figure out the trick? You don't want players mistrusting every potion of healing they find. I want to find the person who came up with this idea and give them a potion of "healing"!
I don't know what is a better idea but just saying I really don't like this "trick"
* Aftermath
** 1) This could be worded a bit better. First "the answer" is a bit vague. I'd suggest referencing the star door and it's code directly. And if there is a minute until the door opens you should remind the DM that that amounts to 10 rounds (6 seconds per round).
Scene 3
* Bad Company
** 1) This would be a great place for some read aloud text - what does their leader say for example?
** 2) "Mercilessly killing them?" I'm not sure the PCs signed up for a TPK
I think taking all their stuff and leaving them unconscious (and potentially branded as criminal tomb raiders) would be enough. Or at least leave it open ended for the DM to determine their fate.
** 3) Battle section: typo: "ruse" not "rouse"
** 4) Blinking Raven stat block: Nimble Escape is the standard trait for your "Quick Escape" in the MM. Also not sure why they get a +4 on their melee attack with no strength modifier (and +2 to their damage)?
Aftermath
Some potions of healing might be good to find on the ravens? 1d4 potions of healing?
Scene 4
* The Treasure Tomb
** 1) "Deep vertical descent" is that a ladder? How did they find any route when surrounded by magical darkness?
** 3) Painted. Flat paint or beautiful murals?
* Floor 1 Treasure
** 1) The pendulum blades aren't described until they activate (another need for some boxed text)
* Floor 2 Magic Items
** 1) Kingslayer sword: Damage is doubled? Also there is no "sword" in the PHB, is it a shortsword, longsword, greatsword?
* Floor 3 The Golden Mirror
** 1) How firmly is the mirror set? Does it require thieves tools or such to remove without damaging it?
Scene 5
* Mummy returns to life
General comment: My general feeling with how you've approached this is it's kind of turning into a bit of a boardgame as the PCs are chased around by the mummy? I'm not sure D&D is designed to support that.
** 1) I think it's a mistake here to avoid initiative especially when the mummy is imposing conditions on PCs that last until their next round. Instead I recommend that the Mummy is in its Lair and takes a Lair Action on initiative slot 20, where It can move and make an attack against a PC. Perhaps legendary actions are making parts of the tomb collapse near a PC?
** 2) You're describing goals for the PCs rather than providing the DM with tools to communicate the peril - the DM doesn't want to assume goals for the PCs.
** 3) I'm not sure how the mummy knows the area well and also blindly triggers a trap when it first appears. I know you want to communicate that it's invulnerable but this doesn't seem to work.
** 4) Mummy Stat block. This seems quite unconventional. I've never seen a monster with N/A hit points.
I think you're looking for the regeneration trait. I would say one of it's lair actions is to "regenerate to full HP" (so instead of moving, if the PCs can get it to zero HP it collapses and then gets back to its feet and resumes the chase - that seems pretty scary. "It won't stay dead!!!" I would say it's resistant to some (piercing, lashing, bludgeoning, radiant etc) and immune to some damage (cold, necrotic, poison). Hero Throw is not a real attack
Fling might be a bit more evocative? Also how does it get +9 on its attack? It has +4 strength modifier?
Scene 6
* The blocked exit is a bit confusing. But I'm not sure I can recommend any improvement there.
On the Homebrew Rules, I think the stealth rules are too complex for such a minor scene. You want the PCs to get into the catacombs, so it's more flavor than anything else. The stealth rules don't play a part in the body of the adventure, so I'd recommend ditching them. (and the tweaks to advantage too)
The codebreaking and traps are the jewels in this adventure - let them take center stage (and the DMs extra attention)
I hope you don't get disheartened by my feedback, this looks like it would be a lot of fun. Good luck!