With the last few Hearthstone expansions, the long-running competitive card game broke free of any direct relationship to any one specific Warcraft title - whether that be World of Warcraft or Warcraft III. From disco-parties in castles, islands filled with dinosaurs, or delving deeper into dungeons in search of treasure, Hearthstone consistently uses the rich lore found in the Warcraft universe to create fun, bright, dark, familiar, memorable, and always entertaining experiences.

But, it wasn’t until the release of the latest expansion, the excellent Kobolds & Catacombs, where Hearthstone nailed its approach to the idea of a single-player mode that you could keep coming back to. That expansion’s Dungeon Run, gave players specific decks where they could then take on a seemingly random order of bosses at increased risk and for greater reward. Available now to all players, The Witchwood deals with that age-old theme of a spooky forest filled with creatures and monsters and of course, an evil witch – Hagatha. In addition to the new cards and abilities it also introduces a new single-player mode called Monster Hunt.


“We knew that the Kobold structure was awesome and super fun,” Lead Initial Designer, Peter Whalen tells me. “We release an expansion about every four months so that means we have about four months to work on any particular one. And with the mission team, that's how long Monster Hunt was in development.” Using the same structure of delving deeper into a single thematic location to challenge new bosses is very-much Kobolds & Catacombs. But the team didn’t stop there as it expanded on the concept by introducing four new single-player classes, abilities, spells, and other changes to better suit single-player Hearthstone.

“We don't have to care if the other guy feels bad, we can make all sorts of cards that feel incredibly good for you and really bad for your opponent,” Peter Whalen on the freeing nature of designing single-player mission content versus the overarching core that is Hearthstone multiplayer. “The AI doesn't have feelings in that way, so it's totally fine for you to be taking a whole bunch of extra turns or stealing all of their minions. It's incredibly freeing to be able to do that kind of thing, make your opponents' minions cost a lot more mana. With Monster Hunt we get to try out all these different ideas that we couldn't possibly do in the collectible set.”


Although four months may not sound like enough time to develop, test, and implement a new feature rich single-player mode into an already established title – one that is also getting well over 100 new cards - the process itself is iterative. In the sense that the Hearthstone team can build on what has come before. In the case of Monster Hunts versus Dungeon Runs, the new spooky forest theme allowed for just that.

“Even if you played a bunch of Kobolds & Catacombs [Monster Hunts] are still fun, and different, and interesting,” Peter adds. “We have four entirely new classes, essentially. We have these four characters, Tess, and Darius, and others that you get to play that have new hero powers. Toki gets to reset the turn, and so on. And this is in addition to having unique upgrades that are essentially the treasures you had from Kobolds and Catacombs.”


But even in terms of tangible in-game rewards the team was able to utilise the new playable classes to tailor upgrades specific to a certain playstyle or character. And then use everything in the lead=up to one final battle. “We really wanted something where after you've done a bunch of these Monster Hunts, how could we tie it all together?” Peter explains. “So, we added the Hagatha fight, which is really the tag team battle where all of the heroes go in together against the big bad.”

Free to explore new ideas an introduce new concepts into Hearthstone via Monster Hunts certainly had its fair share of challenges. Implementing Toki’s Hero Power which essentially resets his turn, a first for Hearthstone, proved to be something that required the help of the engineering team. “That was one of the trickier things that we needed to get in, because some of the UI flow needs to be a little bit different,” Peter tells me. “Just figuring out how all of the pieces work together takes a fair amount of engineering. We have a gameplay engineering team who helps us out with crazy cards, and with hooking up some of the UI things like Toki’s Hero Power.”


Teams within teams is par for the course when it comes to working on games with multiple modes, balance updates that need to be timely, and new expansions that release throughout the year. “The mission team is play testing constantly,” Peter adds whilst confirming that the entire Hearthstone team also play tests once a week for a few hours.

“It's actually a little bit easier to play test mission content because you don't need anybody else, so you just hit the button,” Peter continues. “Plus, we have tools to go to a boss, or to cheat a deck if we need to.” Testing not only to see if ideas work or are fun, but also to further refine the design and even make fundamental changes. “We iterate a lot, especially on single-player content. For Witchwood, an example is that early on you could choose what boss you were going to play next. It would present three different bosses, and you would say, oh I want to fight against Shudderwock, because I know that Shudderwock can give me his uber-treasure. All the different monsters have treasures associated with them. That ended up not being that cool, because people didn't know all the different bosses, and it sort of locked in the treasure decision before you were comfortable.”


Whilst this is happening, as players come to terms with the current decks and card the Hearthstone meta evolves and changes. So even though the final design for an expansion is “locked” a few months prior to release, fine tuning and stat changes can happened right up until release. “Not literally the last minute, but we have the ability and change cards until very shortly before an expansion comes out,” Peter confirms. “Maybe we need to make this a little bit stronger, maybe we need to make this a little bit weaker just depending on exactly how things have shaken out.”

On the other side of the spectrum the earliest work on a new Hearthstone expansion occurs about a year before release, which is when initial design happens. The final push comes in the four-month window between expansion releases. It’s a model that ensures everyone from art, sound, engineering, and design are continually pushing Hearthstone forward. Which is why it’s always exciting to see where we’re headed next.