This causes the territory to be impassable for from a month to a year. Further, revolt is contagious, and it can be awe inspiring to see the much- fought over central asian or european plain suddenly throw all the imperialists out in one xenophobic rush. The movement system is unique among computer games, so far as I can tell. Each turn, you invest resources in buying land and sea movement for the next turn. In the early turns especially, this can be your largest expenditure, and thus calls for quite a bit of forethought.
Naval combat is basically nil.
If someone is coming the other way, you have to invest more points. All in all, I thought it was quite a bit of fun, and may become more so once I learn how to use the miniatures system well. This is random, with about a quarter of the world's territories being scattered to the various players, the remainder starting neutral. And for gosh sakes, even the public domain Risk let's you choose starting positions. Games that admit defeat are all too rare.