Each side gets their own deck of cards. There are 7 different types of cards (tanks, infantry, heavy weapons, paratroopers, artillery, special forces, and airstrike), each with their own powers (but again, these cards could've easily been re-themed to be dragons, knights, and wizards, or Ewoks, Stormtroopers, and Wookies. So if you don't like the WWII theme, just try and ignore it. There really is a clever little game here).
The game starts with one card in the middle, Hill 218. Each player has a starting spot on either side of the Hill card. You take turns placing your cards around the hill in kind of a grid form. The special abilities of the cards determine where you can place cards and how you can get rid of the other guy's cards. Some cards can be place next to other cards (like infantry), some cards can be placed diagonally from other cards (special forces), and some can be put anywhere (paratroopers). Some cards can get rid of other cards by themselves (tanks, artillery), some cards need the support of other cards to do this (paratroopers, heavy weapons). The object is to take control of the other player's starting spot. If you can manage to do that, you win the game.
It really is a fun, clever game that plays quickly, like 15 minutes or so. Perfect for when you have just a few minutes at lunch and you want to play something. It's also quite portable; you can fit it in your pocket.
Since the game is just a pack of cards, it's pretty cheap. If you found it in a hobby store, it would probably cost you about $10. Online, you can get it for around $7. But the best thing is that they've made a computer version that you can play by yourself or with a friend (LAN only though). You can go here to try it out yourself.
The AI is pretty good. The first few times I played it, it destroyed me. I'm pretty new to the game, but am starting to get a grasp of it. It took a few plays to begin to figure out the best way to use the different cards. At this point, I can hold my own. I even won once!
Anyhow, if you're ever wanting to waste some time on the computer and find yourself firing up a solitaire game of some kind, try out The Battle For Hill 218 instead. Even if you don't like war games. Just give it a try. Once you start to understand some of the tactics, I think you'll be hooked.
By the way, if you're interested in purchasing the actual card version of the game, this thread might be worth a quick read. It sounds like they're close to selling out their initial print run. But they're considering doing another printing with some extra features.