"The rhythm is the thing," says Soul Fjord composer Austin Wintory. "It's the thing of most importance. The melody and baseline act in service of the game experience, but it's the beat that's tied directly to the core mechanics." Upcoming Ouya exclusive Soul Fjord, the latest by Portal designer Kim Swift and the good folks at Airtight Games, is a combination rhythm game and roguelike. By necessity, the game must play with hards and softs -- peaks and troughs in intensity and difficulty, some of which are hard to predict, due to the random level generation. Well-known for his adaptive scores in games such as flOw and recently The Banner Saga, Austin Wintory is perhaps uniquely suited to bringing a dynamic and pleasurable audio experience to such a game. "Earlier prototypes were much more complex about responding to events on the screen," Wintory tells Gamasutra. "For instance, we had a series of overlapping guitar lines that would come in when the player takes damage, with the idea being that that sort of jarring dissonance would create an appropriate feeling of distress. But what we found was that it was too much. The roguelike nature of the game, with all the quick rises and falls, meant it ended up having too many shapes." The current system is a lot more elegant, with an emphasis on rewarding success than punishing failure. The result is a more "compact" adaptive score, in which guitar lines are tuned in proximity to enemies and attacks synchronize with the baseline. "'Funk' can mean a lot of different things," Wintory offers. "For this, I didn't want to channel the stalwarts of the genre so much as inject the music with its own personality." Meanwhile, the Nordic overtones to Soul Fjord's funk vibe, which plays out across its visual aesthetic as well, draw heavily from the imagination -- since musicologists don't actually know very much about what Viking music sounded like. Coming off of his work on Stoic's Banner Saga, which bears out of a similar setting but "a completely opposite tone," Wintory found he could piggyback off that feeling to discover the "overt silliness" of Soul Fjord. "Think of the imagery and sounds that a phrase like 'raw turkey leg' summons up," Wintory suggests. "That's the sort of 'Vikingness' we're after here."

'Unheard-of enthusiasm'

Airtight Games tooled around with many concepts for its rhythm game, and pitched its 'Viking Funk' aesthetic to several companies. Ouya met the team's pitch with, in creative director Kim Swift's words, "Totally unheard-of enthusiasm." "Usually developer contracts can take around something like three months," Swift tells Gamasutra. "After we pitched it to Ouya, [company CEO] Julie Uhrman said 'How about we sign, oh, next week?' So that's been amazing." Airtight did extensive research into Soul Fjord's influencing genres -- rhythm games and roguelikes -- to find a perfect balance between the two. Pyramid's Patapon and Edmund McMillen's The Binding of Isaac were among the game's touchstones. "It was a matter of figuring out where we wanted to lie on the spectrum between those two types of games," Swift explains. In search of that balance, Soul Fjord ties challenge with the beats per minute of each level's distinct song, allowing Wintory's "simple but not simplistic" dynamic score to scale with the roguelike difficulty. "Playtesting has been hugely essential to fine-tuning the sound of the game," says Wintory. "When an audio designer comes onto a project, the first question should be: what is the technology capable of? Then the next thing is to dive right in and get your hands on it, preferably from the earliest prototypes possible. I wish more composers made that part of their compositional process. It leads you down paths that thinking in the abstract simply can't." Soul Fjord arrives on the Ouya on January 28th. You can learn more about the game's development process from its official website.