I played through one run of the Demo (20 turn limit), which is about how long it took me to figure out the basics. Here's a rundown that's probably both missing important pieces of information as well as being occasionally wrong. First impressions and all of that. Onward.
Resources and Action Points
There are four types of resources that you'll need various amounts of in order to play your cards. Your Stronghold gives you one of each per turn, but you can get more by conquering ruins and probably other sites (I've only seen ruins/destroyed cities). On top of that, everything you do, including drawing new cards, costs Action Points. You'll either get 6 or 12 AP's per turn depending how you do on your turn initiative roll. You can spend resources to get more dice for this roll, but that only helps for that turn. There are probably other ways to get more turn dice (cards? locations?), but I haven't seen them yet. Deploying stronger cards costs more than 6 AP, so you'll need the initiative for those.
Units and Armies
To venture out of your Stronghold, you need to create an army. Each unit card has a move distance as well as attack/defense scores, attack range, hit points, and resistances (nuclear/biological/chemical/psi). Some units also have special abilities, which can give you more strategic options. A couple that I had were stealth and recon, but I'm sure there are more. There are also combat bonuses, which do all sorts of different things once you're in the shit. Generals lead your armies, and add their own bonuses and abilities to an army which are primarily tactical. Unlike normal units, General cards are pretty cheap to deploy, but offer some interesting effects and abilities. Some examples were +2 to Supply range, Combat retreat options, Assassination, and Sabotage.
Damn the Torpedoes!
Combat I really enjoyed, and it has surprising depth. First, you arrange your units, the front line being where most of the action is. Then you play through successive combat rounds until someone either retreats or loses. Each round has an initiative roll, then combat plays through one phase per unit with you choosing when each unit attacks. There's no downside to attacking since there aren't counterattacks. It's IGO/UGO, attack vs. defense, with each player deciding which unit attacks when and where each phase. Units only get one attack/move per round, so the round goes on until every unit has moved. You get one attack die per point of attack strength, and one defense die per point of defense strength. They're not actually dice, though, it's a success/fail system. If you get more successes that your opponent, you either hit or he misses.
Facilities and other Stuff
There are a bunch of other things I don't even want to go into much until I play around with them some more. Facilities that can add functions to your base as well as resources. For example, I had a General with the Tactics ability at my base which had a War College (or Academy or something). He sat there making Tactics cards, which go into a universal pool and can be played in combat by any General. Basic 1 AP cards were pretty easy to make, and gave bonuses like +2 attack dice or +3 Fate (Fate can be spent to influence dice rolls). The +2 AP cards were trickier, and gave slightly better bonuses like reroll 3 opponent's successes. The +3 AP cards were really hard to make, but gave great bonuses which I don't remember offhand. Anyway, apart from Tactics cards, there are also cards that can be created by Technologists or Geneticists with the appropriate facility. You can also upgrade your Stronghold and facilities, but I'm not sure what that does.
The Good, the Bad, and the Interface
There are some aspects of the game that could stand to be brought up to speed. I keep trying to do things like grab the terrain to move the map, the interface is kind of 1980's-ish. It's functional, just neither pretty nor intuitive. I did like the unit art and the terrain, and there is definitely meat to the game once you work out what you're doing and what things mean. I have no idea how the AI is, I didn't even see him. I only fought zombies and things in the ruined cities around my base. The game was interesting and entertaining enough for me to buy it, but YMMV.