Ever played a Hearthstone match that gets completely out of hand before you even have a chance to fiddle with the backgrounds? If you're a devotee of Blizzard's glorious collectable card game, there's every chance you carry painful memories of an early knockout at the hands of a Zoolock. Or that now-forgotten army of Murlocs who pulled together a victory against you by turn 4.

But have you played a match that was certifiably crazy by the end of turn one? Such possibilities await in Blackrock Mountain, Blizzard's next Hearthstone adventure, which is due to go live in April.

Picture the scene: I'm pitted against Coren Direbrew, the first of the expansion's 17 new bosses, whose zero-mana automated hero power will draw a minion from both decks onto the board. Merely seconds after I've exchanged greetings with the AI (don't pretend you don't do it either), two cards drop. On my side, a Cenarius. On his, a Mal'Ganis. That's turn one.

After laughing, Frankenstein-like, at the sheer absurdity of it all, it becomes clear that this isn't the sort of challenge where a Knife Juggler is going to cut it by turn two. Your meticulously arranged ladder decks have wound up in the wrong tavern, pal.

"We want people to look through their old cards and a light bulb goes off"

Eric Dodds

It's an exciting prospect for those who found the theory-crafting aspect of the Naxxramas adventure so enjoyable. That previous adventure forced players to build custom, one-time decks to play their way around immensely powerful foes with a mystery Achilles' Heel. Finding that weakness, and building a deck that could exploit it, was just as fun as pulling off the victory.

"We really liked the Maexxna encounter in Naxxramas, where you had to build a whole new deck," says Eric Dodds, Hearthstone's lead designer. "Normally you wouldn't have a whole deck of seven and nine drops, but in this case it's absolutely a good idea."

After calling time on Direbrew with a swift 9-attack haymaker (pro-tip: Rogue's Sap spell is essential), I sat down with Dodds to discuss the expansion, as well as the smartphone version and, somewhat awkwardly, the ESL controversy.

GameSpot: From what I've seen so far of Blackrock Mountain, it appears that the Hearthstone team wants to bring focus back to the original card set, as the spotlight is currently on the GvG cards. Would that be a fair assessment?

Dodds: Well the intention at a higher design level was really that players really like dragons, so it would be awesome if they could make a dragon deck.

The new Blackwing Technician card will be a good example of that. It's a 2/4 that costs three mana, but is 3/5 if you have a dragon in your hand, which is a pretty effective card.

We love the idea of people building their deck around dragons. Up until now, you could put Ysera or Alexstrasza in your deck, but we wanted to support that a bit more. We actually really like the idea of adding new cards that make you want to play the old ones again.

A good example of this is the new Shaman spell, Lava Shock, which suddenly makes overload cards much more compelling.

I'm guessing it will also encourage people, when they're buying cards, to choose the classic packs instead of GVG. Certainly at the moment I'm finding myself opting for the GVG packs, because there's still many of those I don't have, but there were a few classic cards that I missed too. Is it the intention to bring focus back to the classic packs again?

Not really. I mean, we're bringing attention back by saying that this card you already own can now be seen in a new light. We want people to look through their old cards and a light bulb goes off, and people suddenly have this idea of how to use them in an awesome new way. That's very exciting to us.

I did want to get some insight into how you internally test and balance these new cards. I know that you play the game incessantly to get a feel for them, but I've always wondered if you used any algorithms to test your cards, and whether you internally score things like batttlecry.

It's interesting because when I first started working on Hearthstone, I had played a ton of other [collectable card] games and I thought, oh it's great I can have spreadsheet and it's going to tell me how much everything should cost. It turns out that this is absolutely not what we do at all. It's certainly what I thought we would do, but there are so many factors that go into balancing cards, such as what hero uses them, that really what we do is assess on a case-by-case basis.

A designer creates a card, and tends to have a gut-instinct on how it's going to work, and then it goes over to our balance team. Now, our balance team is four amazingly skilled guys. I think all of them, at one point or another, have been in the top twenty legends. They are phenomenally good at the game. They take these cards that we're making, and play them and play them and play them, and they come back with the numbers that these cards should be released with.

That's incredibly interesting. It makes sense too because there are some cards that look better on face value than in practice.

What we love is when we see players' reactions to our new cards and they say "how could you do this?! How could you print that card?! It's broken!" We have actually seen that a few times before, but when you get to play it, people tend to realise it's not the be-all and end-all.

"Our balance team is four amazingly skilled guys. I think all of them, at one point or another, have been in the top twenty legends."

Eric Dodds

There are instances where the facts lie too. For example, I tend to prefer a card with six attack over seven, because it circumvents the Big Game Hunter.

Yes that's certainly the case now in the meta, but we'll see over time if the Big Game Hunter cycles out and those 7 attack cards become more powerful.

Let's talk about the smartphone version, which I know is a few months away from launch. Will it all remain cross-platform, in that an iPhone player can play a iPad or PC?

Yes absolutely, it will be your exact same account, so all your cards on tablet or PC will be available on your phone too. When you start a match on a phone, you could be playing someone on another phone, someone on a tablet, on a PC, who knows? It's all one big ecosystem.

One fear I have is that the game is going to take hold of my life now that it's in my pocket. Would you ever be open to the idea of self-suspending accounts, just for a little while, if someone needs to lose the distraction for a few weeks?

[Dodds Laughs]

Seriously though! If I have a big assignment that needs completing, or someone has exams to study for, it could be handy to suspend your account for a brief while.

Well, I don't that's in the near-term plans. But I think one of the neat things about it being on the phone is that, very often, people find themselves with a spare ten minutes with not much to do. So I think the phone version will make Hearthstone fit into your life a lot better.

Will it destroy my phone battery? When I play on iPad, I need to keep the power cord plugged in...

It's certainly... it's a beautiful game, so it definitely uses power. One thing we're constantly thinking about is how to make the most of the phone's battery.

When you start a match on a phone, you could be playing someone on another phone, someone on a tablet, on a PC, who knows? It's all one big ecosystem.

Eric Dodds

Hearthstone's an always-online game too, so would it eat into your monthly 4G (LTE) allowance? I presume you would advise against people playing it on their phone if they have tight data usage restrictions?

I don't know if it uses a lot of data. You have to have a constant connection though. I wouldn't recommend playing it on a train.

I wanted to address the elephant in the room--the ESL Legendary series, where people on Reddit discovered that the winners had retroactively been given Blizzcon Qualifier Points. I suppose the main question is, do you have some level of regret about this?

I'm not sure what you mean.

So, the main finalists of the ESL Legendary series each won World Championship Qualifier points. Silent Storm, who came in first, won 100 points, which is the equivalent of getting two 1st places in a ranked season. One problem people have is that it wasn't ever announced as an officially sanctioned tournament. Were you not made aware of this?

Yeah, okay, I'm not as involved on the eSports side of things.

[Blizzard PR: "I think the best thing is to take that question to our eSports team"]

Okay, well that would be great because there's a lot of questions people have regarding it. [Update: As of press time, Blizzard has not yet officially responded to the question].

I wanted to also ask about buying card packs. At the moment I opt for GVG packs, but doing so means there's no chance of getting the final few classic cards. If I buy classic packs, there's no chance I'll get the final few GVG cards. Would you consider grouping these packs together in the future?

It's certainly something that we've talked about a lot, asking what is our long-term plan for packs of cards. We don't have anything planned right now, because at the moment it's only two kinds of packs, but it's certainly something that in the long term we'll be looking at.

Now it's all in the past, what is your overall view of the GVG update?

I loved it! I thought it went amazingly well. We certainly liked a lot of the randomness that was introduced, because you're never quite sure what's going to happen, but skilled players can figure out what to do in those situations.

I'm also a big fan of the Goblins Vs Gnomes style. I think the look and the charm is very Hearthstone. I like changing things up--you saw how Goblins Vs Gnomes was one style and tone--and now Blackrock Mountain represents a more serious tone. I like how we're encompassing different parts of the Warcraft universe.

Blackrock Mountain will also add 31 new cards, which I think is an ideal size. Personally I felt there were too many GVG cards that were introduced and never used. For newcomers, the number of cards must start to become overwhelming. Surely, looking forwards, the sheer volume of cards is going to be your long-term enemy?

It's an ongoing thing that we're always talking about internally, because on one hand you've got players who are always looking for new content, and on the other hand you've got players who don't want to be overwhelmed with new cards. I think you hit the nail on the head with what we're trying to do with Blackrock Mountain, because we want to change the meta again, but we don't want to add so many things that players become overwhelmed.

I'm guessing you're also fairly happy that there's no major discussion about nerfs at the moment either. I suppose the likeliest candidate is Dr Boom, but I don't think the majority of people are complaining about it.

Well philosophically it's our intention to never get to a situation where we need to nerf cards. The only time we would consider it is if the card staying as it is would be damaging to the fun. We changed Undertaker because you were seeing a lot of decks based around that, and so we didn't have as much diversity, but actually right now there's a bunch of different decks.

So, as long as there continues to be a bunch of different types of decks, we really have no interest in nerfing anything. And out long-term goal is to get to a situation where we change as little as possible.