Risk I know and like.
Castle Risk, I don't know.
If I remember well, you played a country over the years in a kind of real time thing.
There were provinces, in which you could recruit troops and boats.
You also assigned collected money to building cities (through a special unit and they grew depending on the area they were build in), research, trades and army...
You declared wars, concluded treaties, attacked cities and troops with generals or admirals that gave bonuses (I think there were bonuses for tech levels, number of troops and so on).
Units were also getting tired and needed to rest or they just get back (meaning that for exploration you needed to settle new areas).
The game was won with points.
I think the best game I had was playing Portugal in the Age of Exploration where I stayed out of troubles in Europe, discovered America, inland America and the Pacific Ocean as well as the Horn Cap.
I was also getting to India through the South of Africa and had managed to settle new "cities" in good strategical points to support my explorations.
My main problem at that point was that I had a small population with a small growth rate and not enough money to build a huge colonial empire (rather historically accurate I think).
I never finished this game but it was fun.
