Thanks for playing! Interesting that you think the sprint could be slower. Unfortunately I can't immediately think of a way to increase the walk speed but decrease the sprint speed because of how it all mechanically works together. The player needs to be able to sprint a bit faster than the monster can run so you're able to get away, the monster in turn needs to be able to run significantly quicker than the player can walk so that he's able to easily kill you if you've run out of stamina. Head bob and player footsteps were on the list for the last day but alas I didn't have time.
With regards to visual variety yes and no. I like the fact it can have a labyrinthine 'all these corridors look the same' feel but it's probably not great if players need to entirely rely on the map for navigation. I did originally plan to include some props to break up the environment a bit (again I ran out of time) and I guess they might have helped with locating yourself.
Yeah, I did consider having an instant game over the first time the monster catches you but I figured that it might be super frustrating, especially if you were near completion. So I included the personal protection device as a one-time 'have another chance' mechanic. It's not mentioned before it happens so I figured it shouldn't reduce the tension a player would feel (at least on their first playthrough of course).