I figure, caution to the wind. I'm going to have a go at a completely vectorized graphical look for the game. Not only will it give In Profundis a distinctive appearance, but it's both easier and faster to apply dynamic graphic effects to the game, such as, say, in making liquids look more visually appealing and to producing the "outline effect" for regions outside of the player's direct view. It would also look somewhat closer to the pitch videos I posted to YouTube a year ago.
So, my current objective is to implement this system in pyglet. After that, it's probably time to go in and scale back the random generation a bit, which after some thought I think is a bit too random. The game world was more interesting when it was just a big blob of random shapes than the rather too strictly laid out shafts and corridors of the current system.