Blizzard's Hearthstone: Building a truly digital card game

Blizzard, makers of wildly successful video games World of Warcraft, Starcraft, and Diablo, shifted speeds earlier this year when it released its own free-to-play digital card game, Hearthstone. Based on the lore of its Warcraft universe, the game is available on Windows, Mac, and iPad.

Last week saw Blizzard wrap up the launch of Curse of Naxxramas, an elaborate solo adventure expansion for Hearthstone giving players a chance to step away from the standard multiplayer focus and into a themed series of battles to test their skills and reward the successful with powerful new cards.

As the launch event drew to a close, CNET had the chance to speak to Hearthstone Senior Game Designer Ben Brode and Lead Artist Ben Thompson, about both the experiences found in the expansion and the wider effort to build a card game that takes full advantage of what you can do when you've created a truly digital deck of cards.

All of Naxxramas is now open, so how does it feel to have it fully released? What's been the reaction so far?

Brode: It feels awesome. I've been really happy with the reaction. I've just had some feedback today about the way people enjoyed the Kel'Thuzad fight [the final boss battle of the expansion], in particular, and we put a lot of time and care into that to really bring him to life. You've spent the whole of Naxxramas listening to him taunt you over and over again and you finally get to take the fight to him and hear him taunt you for the last time. People seemed to enjoy it and that was really gratifying to put a cap at the end of this long release event.

I was beaten soundly by Kel'Thuzad on my first few attempts and it showed that he had plenty of variety in his victory taunts as well.

Thompson: That was a big part of the Naxxramas experience as a whole for us. It really meant we had an opportunity to reinvent Naxx from a different perspective, in this case, the perspective of Hearthstone. To make it more friendly and approachable, while at the same time taunting. Kel'Thuzad, instead of him being a super villain, making him more of a super jerk.

You certainly made it clear that the final boss wasn't going to play by the rules.

Brode: Something I wanted to try with Kel'Thuzad was breaking the rules a little more. I mean, already the bosses of Naxxramas break the rules. They have hero powers that are just not fair. They're playing with more than two copies of some cards in their decks and they're playing with cards from multiple classes. With Kel'Thuzad I thought "What if we just ramp this up even more? What if he doesn't even play within the space of Hearthstone? What if he takes over your turn while you're playing it?" I think that all helped to make Kel'Thuzad have that next level of uniqueness.

In some ways the solo adventures felt less like Hearthstone the 'card game' and more like Hearthstone the series of chess puzzles.

Thompson: For sure, that was a big part of all of these encounters in Naxx. The opportunity to not just get you some new content in an exciting way, but so you felt like you'd earned it. Not just buying the wing, getting your cards, and moving onto the game. But, you know, really earning them. Something you feel like you came by in an adventuresome way.

At the same time, also just doing so in such a way that you got to play smartly and come up with good ideas or clever tricks and play against the bosses' jerkiness. And while doing so, maybe learn to play certain cards you wouldn't normally put into a deck or to approach a class in a new way or maybe play a class you wouldn't normally play at all. That's where the class challenges came in. We really wanted you to discover new parts of Hearthstone that maybe you knew about and maybe you were aware of but you'd never really had the opportunity or the excuse to play with.

So this expansion has delivered lots of new cards. I get the feeling some cards in Hearthstone are designed because they're fun while others are designed to be particularly competitive?

Brode: Definitely different goals for different cards. And you may look at a card and think -- like Angry Chicken is a card that is definitely designed to be fun. But if someone ever discovers a way to make that card competitive then that's awesome too. And often we kind of put tools in the environment to allow players to find both competitive decks and fun deck types. And sometimes those overlap, but we're most concerned with making sure there are at least some fun cards.

Thompson: Our game director, Eric Dodd, spent a lot of time working with Brode and the rest of the design team to really develop what he likes to call, and what I love about the game itself, is real story moments. Opportunities for player stories to take centre stage. And there's definitely cards in the Naxxramas bunch of cards that do just that. They're really going to change the way games play out, not just against AI but also other players. And they're going to find ways to use these that we haven't even thought of yet. That's as exciting for us to hear those stories as it was for them to experience them first hand.

What aspects of developing Hearthstone and Naxxramas have really made you feel like you're fully exploring the digital card game concept?

Brode: That is something I love to explore. There are a lot of very exciting things in that space. Obviously the Kel'Thuzad fight is one of the things -- him surprising you by not playing by the rules -- any time we're breaking the fourth wall of Hearthstone is pretty unique to being digital. Surprises in general on that scale are unique to being digital. The Kel'Thuzad fight inspired us and there have been more discussions about ways to use the digital space going forward, but we're always looking at ways to lean into that and try new and exciting things that rely on that.

A card like the new Webspinner is exciting because it can put a card into your hand that you don't even own.

Brode: Webspinner was a huge success, both in the way the game is played and the community response to it. So we're very excited about the way that card design turned out and we'll be exploring those types of things in the future as well.

Thompson: When you go to Gothik the Harvester's encounter in Naxxramas, and the way when a minion on his side dies a spiritual version of that minion lands on your side of the board and causes you damage. The number of physical tokens that would take or how you would communicate that in a physical space is a lot less interesting or compelling than saying "Hey, this thing spiritually manifests itself on your side of the board from the opponents side." The art is different, and just the general vibe starts to take on more of a "Wow, stuff is changing, rules are different and I need to pay more attention now."

That's really where the art team specifically, but design as well, really benefits greatly from being in a digital space. The communication with the player is done in a very succinct, very minute, very easy level with the visual feedback you're getting and making decisions based on it, and we don't have to have you read three lines of text to understand what just happened or what's going to happen going forward. And that's a very powerful tool and one we want to go to whenever we can or at least as much as makes sense.

Blizzard has a certain polish to its art and execution across all its games. What would you say is distinctly Blizzard in the experience versus other digital card games?

Thompson: It's the unexpected surprises. We use a term a lot during the development of the game and continue to use it a lot going forward: delightful surprise. Something you didn't expect, or maybe you thought could be cool if, but not only does it happen but happens even more so. More over the top, more funny, more charming, and that's something we try to do wherever it makes sense. To play down an otherwise frustrating moment or to play up an otherwise unmentionable moment and dress up the situation even more than you would think.

If you look at something like Brawl as a card, and you play that, the way that would be written textually on a physical card is very "yeah, OK, great, I'll just shuffle these randomly and pull one out and we're done." But the Blizzard way of doing that is to have these guys jump into a dog pile in the middle and stars come out and dust is flying and you're like "Oh my god, please let my card win, please let this happen for me" and you're either greatly surprised and happy or you're "oh man, bummer". But the experience was fun, and the experience engendered a story for later to tell your friends.

Brode: The other thing I think that makes Hearthstone uniquely Blizzard is its ability to take a game and make it both easy to learn and really hard to master. I think there's a lot of games that are hard to master but maybe not very easy to learn. With Hearthstone we've seen people who are not traditionally gamers come in to play it and they love it and then we also have this really high level of play that's happening at the e-sports level.

In my games I've occasionally bumped into players who have reached the Legend rank, but I haven't felt entirely out of my league even though I pretty well am. Was I lucky or is that designed too?

Brode: One of the things that we tried really hard to preserve in the concept of Hearthstone is the little victories. It's something that makes Hearthstone fun even when you're going to lose to someone much better than you. Because you at least get to play your awesome cards and destroy some of their minions and play the game. So those moments throughout the game, even when you lose, hopefully you'll at least do some powerful things and you really did something. It's something we've always tried with our card designs and we've tried to preserve that feeling that is important to Hearthstone, the feeling that the game is winnable.