Ok, I can see that... With that in mind I think it partially works and partially doesn't:
The size of the dungeon really gave me the sense of this being the player's first 'big' quest chain. The kid gloves have come off, and this is where things get serious... And it does have a few milestones that break up the combat grind; finding the key, finding the pastor, the pieces of the ritual and their related conversations, the layers of the dungeon, etc.
That said, those milestones just aren't as meaningful or rewarding as the ones you set up in the early game. Sex is one of your key milestone rewards, but there isn't any for HOURS. Even camping in the dungeon doesn't throw up an opportunity... After sex I think your next best milestone reward is interaction with your companions. Not necessarily sex, but the innuendo or flirting is conspicuously lacking suddenly, especially if Samara got her voyuer on back in town. Or some other conversations that aren't just one of the companions expositing on some question mark; insights into their likes and dislike, a promise to do a thing, or help with a thing, or buy a thing when possible. Basically grow their friendships... Next would be clues to the main story elements, hints about Sa'id's role, Lady Wolf's background, insights into places we've been, or will go to soon, that sort of thing... Finally rewards for thorough exploration. Parts of a codephrase for a secret hole-in-the-wall back in town for example, it could open a rare vendor or a hidden sex scene or even just a funny/interesting room with patron references. Or just something silly, like a Blackfur costume that would guarantee you win the bet, long after you've probably already won it. Basically things that link the dungeon back to the larger world and make it less self-contained.
On a related note, I'd consider doing something different with the tilesets... You go from a basement to a sewer system? Why does a little town like this have a sewer that's far larger than the town itself? It makes no sense to me, unless it's plot-relevant later? Personally I'd consideer reusing those assets for something entirely different back in Kaldea and making the lower level of the dungeon something more unique... For a cult hideout I guess something cave-like or hellish would be the standard trope, but I'd love to see you go wild with it. Something that gives me more of a "wow!" moment when I first go down below the basement layer.
Finally, there's just way to many level-ups involved. Like, 10x too much XP available. I'm still there on the sewer layer after playing for another 2 hours or so, and I've now maxed out both Samara and Hiho. There's nothing left to spend their skill points on (unless I'm missing something?). Whether you want to shrink down the levels, or thin out the mobs, or just lower their XP values is up to you. Maybe some combination?... It's just far too much power-creep (or at least it will be when some of these skills work as intended).
