This is a great writeup on the castle of good hope! I was previously aware of the cape of good hope, however now I know that it has a corresponding castle, too - cool! It has a special historical feel as well because as you say it's the oldest surviving building in all of South Africa albeit with various restoration efforts. (On a side note, I get the feeling that there's a thriving South African community in Steemit!)
The model of the fort like a 5 pointed star has quite the imposing look, I've seen other forts or citadels with a similar model and wonder if that is a particularly popular way to construct forts. Maybe it's so that if an enemy gets trapped inside two walls, they're pretty much doomed? But this assumes the fort is built on solid ground, nothing to wash away confidence like rain undermining the walls... Certainly lucky they never got attacked!
The center of the fort has such a different feeling from the outside defensive walls, though - while there are bastions and walls surrounding it, the governor's home is so lavish and the center seems fit for every day life; I guess that the market in the middle was fairly lively in its day?