Unfortunately, I didn't really get started until Monday I think. More stuff came up! However, it is going quite well I think. There is still a lot of work left to do, but I feel like what we have so far is quite promising.
I am currently experimenting with adding a run. While I was on the fence about adding run, I think it is important for gameplay considerations that when a monster is barreling after you, there is something you can do other than just walk away slowly.
I'll have to see how my asthma/endurance idea will work out, but I have a good feeling about it.
The short answer is my fears were unfounded, and I think it is turning out well.