I'm creating my own C++ game engine that aims to clone Pathways into Darkness and remake it so people will be able to enjoy the game once more.
(A custom built C++ game engine using the Allegro game library)
This Engine will use a hybrid of ray casting (For blocks and collision detections) and trapezium calculations (For lines and fake walls).
One of the things that will be gone is the unique PiD HUD. It may be thrown back in at a later date, but a more-compact HUD will be used (One similar to SystemShock 1).