While it was not intentional, it was a part of the FPS controller via Unity's Standard Assets, there is a sprint option with left shift.
I do agree, in regards, to the 4x4 puzzle. It is removed on the next version, which will be updated after the Jam ends.
Polish would be good, though I lack art skills, so those are kind of on a limited basis. In the next installment, there will be a few landmarks added, specifically one in each of the more empty rooms to give the player orientation, and forms of reference to better get a feel for the dungeon itself. Though not a significant amount, given the fact that the purpose of the game is exploration and discovery, I.E. that the player should feel lost while navigating, but it was indeed perhaps too pervasive in the v1 of the submission. Thus the change in v2, due to be upgraded on 8/1/19, in the later hours.