I just realized, this whole series gives me a vague darkest dungeon vibe. Nothing to do but explore the giant haunted estate you're stuck in.
There's definitely a small overlap with the Otter team stories. They're both shown as these episodic dungeon crawling adventures into vast unknown places with sudden encounters against horrifying monsters and cruel traps.
Not quite as on key as that, but this personally reminded me a bit about Operation Abyss / Operation Babel. They're classic 2 row FPS-style dungeon crawlers where you take a team of experts to go hunt down anomalous monsters that appear throughout Tokyo city, and the first mission is going into a gloomy abandoned office building looking for missing people a lot like the rooms in shown in this series.
If you took out Operation Abyss's cyberprep aesthetics and used Darkest Dungeon's tough-as-nails approach to dark fantasy instead, you'd pretty much be right on the money for Arai-San Mansion the game.
