Strange that none of the buildings are taller than the walls of the city, however - not a problem
That's the point of walls - isn't it? To protect the city, so it would make sense that none of buildings are taller than their fortress.

the river as it flows through the city is almost too straight.
I think it's a canal. It looks far more symmetrical and unnatural than the rest of the river, and since it flows so perfectly through the city, I'm thinking it's probably an artificial path. Makes it easier and safer for the citizens to get water than by traveling all the way out of the city, filling up containers, and coming back.