I mean, a United States under North Korean occupation? China, you can maybe swing China, but North Korea? Bit silly. Then again, being written by John Milius, it's not the occupying power that's the point of the story.
The point is that a bunch of Americans get a chance to exercise their right/love for big firearms and go at 'em. Which, as you can see in this trailer, happens a lot in this game.
As for the gameplay, Homefront is a little like Crysis, with the player dropped into largeish areas (like a whole town) and then given a few objectives to complete. So, same game style as Crysis, same bad guys as Crysis...except it's written by John Milius. Sounds good to me.