I really enjoyed the Doctor sprite! The overall walk cycle worked well and you captured the character well. Where was the Shift to run documented? I played through the first game without knowing about it and it was painful to walk so slowly. I'm not sure why that option is really in there. Is there ever a need to walk vs run?
I really liked the procedurally generated maze. Although I think that the overall experience would be better if you generated a much smaller maze, added some additional traps and upped the movement speed of the character. Some additional environment work and tilesets would have made the experience feel a little more full.
On my last game it somehow generated a maze with only one branch in it :) It made the experience pretty easy since there was no need to backtrack and so avoiding the copies was trivial. Maybe that was just a crazy generation though!
Overall keep up the good work!