It's in beta right now, and I have to say it's surprisingly far more fun than I was expecting.
At first glance it seems simplistic, even dumbed down, from other card games like Magic: The Gathering or even the WoW Trading Card Game it has evolved from. I would say that in this case, simpler does not mean worse. It just means very fast (super duper fast) games with almost as much strategy as the other games.
My brother-in-law and myself are both in the beta, and we are both avid MTG fans, as well as veterans of the now cancelled WoW:TCG. And we both can't get enough of this game. In fact. I just noticed it's after 1am here and it's only felt like 20 minutes have gone by (I started playing today around 9 or 10pm).
How to describe the game? Where to start?
Well, it's a digital card game. Which means you need to create and customize a deck (which the game can also assist with). It plays a bit more like WoW:TCG than Magic, (but WoW:TCG lifted a LOT from Magic). Meaning that you pick a class to play, which gives you a unique power that costs mana (the warrior can give himself a stacking shield, the rogue can equip a dagger, the priest can heal 2 points, etc.). The class you pick also unlocks unique cards that can only be included in that class' deck.
Unlike M:TG (but similar to WoWCTCG), the minions you play do not regenerate health and you cannot assign "multiple blockers" to a single attack. In fact, and this is new, you don't play *any* cards when it isn't your turn.
As I mentioned before, that's part of what makes the game as speedy. Each player automatically generates 1 mana on their turn (with some cards being able to increase that). Each deck is also limited to 30 cards (no more, no less).
How do you block damage if you can't play cards on your turn? There are minions with the "taunt" attribute, and these block all incoming direct damage (from other minions and the hero) until it is destroyed. Spells and card-based damage (ie: not from a physical creature or hero) will still bypass them. There are many cards with many different attributes, and this is where the actual strategy comes from.
I've been playing a rogue deck and and I've built it to be a bit more heavy on class cards and less on the minions. It's all about speed, control, and quick damage. It's been doing pretty well for me so far.
Like other card games, there are cards that have all the standard rarity types. Here they follow the WoW nomenclature: Common, Uncommon, Rare, Epic, and Legendary (with some "foil-like" random ones that are called "gold"). How do you get the better cards? Several ways. You get them in card packs, which guarantees at least 1 rare (with a chance for more than one). You can get card packs by completing daily quests (which vary from "winning three games against players that day", etc.), by spending gold coins (which you get by just playing the game as well as completing daily quests too), and also by spending real-world money on them.
"How does blizzard keep that balanced against people willing to spend far too much money on the game?" Well, each deck is limited to just 2 cards of the same type. Plus.... and this is big.... there is a crafting system in the game. This means you can "disenchant" (destroy) cards you don't want/need and get dust for them. With enough dust, you can craft
any card in the game. Even the legendaries. The better the cards you disenchant, the more dust you receive.
"Yeah, but how much dust would it really cost to make some of the good cards compared to how much it would cost to disenchant?" It's not as bad as you might think. An epic (purple) costs 400 dust to craft (maybe 800 for the really powerful ones). A disenchanted epic makes 100 dust. A disenchanted rare makes 40. So if you get a really rare card for a class you never want to play, it's not wasted since you can disenchant it. You can even disenchant commons (albeit for a small amount). I've crafted some really nice cards, more than I expected to as well.
The other way Blizzard keeps it balanced is it has a ranking/matchmaking system. Both my brother-in-law and myself are about 50/50 in terms of wins/losses so it certainly seems to be a truly balanced matchmaking system so far.
The other thing this game has is "arena" play. It costs gold to join, but it's essentially a "sealed deck" play, with chances for some really good prizes (in the form of great cards, more sealed packs, etc.). I haven't done it myself yet, but my brother-in-law loves it.
The game is definitely designed for scalability without becoming broken. It even looks like they may include team-based combat since there are some minion cards with text with "...for each friendly character (hero/player) healed." My hope? WoW:TCG had "raid decks." And they were awesome. One player played the raid deck, and about 3 -6 players would team up against the powerful raid deck. I own Onyxia's raid deck, and man is it a blast for all involved! So my hope is that digital raid decks will eventually make their way to the game.
Like I said, I myself was pretty skeptical about this game. Even after playing a couple practice games against the computer, it felt pretty basic and dumbed down. But dig a little deeper and you'll find that's just scratching the surface of this game and like I said before: less/different mechanics does not mean "worse."