Risk
is somewhat of a generic wargame. The units are represented as a sort
of "strength in numbers", there isn't any difference in the different
playing pieces other that the number of units they represent. In combat
the higher number of units you have, the better chances that you have.
In games that I've played and seen, the combat near the end of the
game often seems to move in a wave of destruction across from one
side of the board to the other, but with a wrong move it can be turned
right around in a wave back in the other direction.
Personally, I prefer games that have different types of combat units,
such as in Conquest of the Empire, with
the Infantry, Cavalry, and Catapults; or some special rules for each
player, such as in Dune, with one player
getting extra movements, or extra cards, or even special abilities
that allow the player to see what to expect in upcoming rounds.
Recently I've heard more about what Hasbro has been up to and I admit
that look forward to seeing how Hasbro has updated the game with the
new Risk 2210 A.D.