With a number of hex grids available to play creating defensible territories, and tiles that award you extra benefits in the struggle (such as bonus units, better defensive or offensive powers, and better vision to penetrate the optional fog of war), Hex War steps outside of the shadow of Risk to stand along as a solid tactical game to play on the move.
One change to note is that Hex War is not a turn based game where you have a go, then your opponent. You plan your moves at the same time as your opponent and then all the moves will happen on the board simultaneously, with combat resolving on the actual moves of both sides, not the estimates you may have mentally made while planning your moves.
Hex War is a free download, although a Pro version is also available in the store for 99 cents / 79p. The Pro version simply removes the adverts from the app, there are no actual changes to the code. I'm sure that a few people will wonder why this isn't an in-app purchase in the code, but this way the app has two chances to appear on some of the ranking lists in the Windows Phone store.