My group finished the Scarlet Citadel recently, a Kobold Press adventure from 2021 that features a small town and large dungeon beneath. The premise is that of a classic dungeon crawl in the guise of 5e. It took us 23 Sessions of about 3h hours each to get through, the party finished with 9th level across the board and featured a swashbuckler rogue, a warlock artificer wizard, a path of the totem warrior barbarian, a gloomstalker ranger and a cleric sorcerer (my group is really into min-maxing...).

The tips on how to run a classic dungeon crawl using 5e as base are excellent, especially the remarks on how to handle passive perception and darkvision were essential for a good experience. I would add to these to include some optional rules from the dungeon masters guide to counteract the "superhero" tendencies of 5e that are somewhat misplaced in this adventure. We used "Slow Natural Healing" (DMG p. 267) to make resource management more important. Also, the use of morale rules helps to resolve combat faster (DMG p.273) and adds some life to the dungeon if retreating enemies regroup, get reinforcements etc. After completing it I would definitely add more rules specifications, in particular I would add a level of exhaustion to a character that went down to 0HP to maintain some tension as characters reach higher levels.

I really loved the town and its characters, it made for some great role-play and I gave the party the opportunity to purchase the decrepit temple to setup as their base. Konrad the old battlemage selling faux magic items was especially great as character.

The dungeon itself was really fun and versatile with lots of factions, tensions and crosslinks. The maps for VTTs were also great and easy to implement into Foundry. Only the overlays were a bit of a hassle, I ended up not using them and just describing the changes, which was totally fine. Overall I would recommend to not set everything up yourself in a VTT, it took some serious work to draw all the walls etc. I think there is an option to purchase or import it, that will save you a lot of time. My player's appreciated that additional work, but if I had to do it again, I would just use Owlbear Rodeo and a bit more theatre of the mind to make the experience less boardgamey.

I essentially agree with two criticisms that Mike Shea aka Sly Flourish made in his video series accompanying his Scarlet Citadel campaign: the module is VERY text heavy and it lacks a clear hook to drive the party to explore the citadel.

The first issue is not easily resolved but I have learned to put up with it, as I usually do a 1-page prep cheat sheet for each session beforehands anyways. But it definetly resulted in a lot of page flipping and me missing important information here and there that was buried deep in the text. Having run some more bare bones OSR modules recently the contrast was quite startling!

The second issue however I didn't find to be as much of a problem, but more of a creative challenge. I resorted to having the portal to the drylands opening further and further letting bigger and bigger threats through, which drove the party deeper underground to find the fix for the problem as soon as possible. Gellert was a good final encounter, I beefed him up with a Neothelid flavoured as "The dark between the stars, the wyrm of the void" at his side, which made for a challenging final encounter. Ultimately a Dracolich came through the Dry Lands portal, destroyed the town and hunting it down is now the hook for the follow up sessions.

I would recommend this module if you are ok with wordy room descriptions, it needs some creative interpretation in parts, but I found this process to be enjoyable. That being set, it is NOT a low prep adventure. 7/10