Overall a cool sounding idea, focussing on generated mazes over combat. Normally I would caution against the procedural generation, however I've seen on Discord that you have already made great progress on that. Be sure to reach out to Ian or myself if assistance with the proc-gen is needed. Beyond this, the concept seems very achievable :)
The concept document was good and detailed in places, but leaves the reader with a few questions around what the scale of the maze is and the exact look of the game, because as the concept art provided is great, more illustration of the game as a whole was needed.