Feature: The Story Behind Biped’s Sound Design

This is a feature article from an external source, provided by audio designer Koozer Zhang Xin, who worked on Biped’s musical score.

Biped is a physics-driven 3D co-op adventure game that highlights coordination between two players. It features a control pattern where players use both joysticks (or the left and right click of a mouse) to control the characters’ legs instead of their whole body. Using their legs in a 3D space, the characters can walk, slide, and perform a wide variety of interactions with objects. The triggering mechanism for sound in this game is rather complex and unpredictable, which poses a formidable challenge to audio design in terms of creating audio effects and programming. Still, handling the challenge proved to be an engaging and rewarding journey.

Biped’s audio designer Koozer Zhang Xin shares his fascinating experience during the game’s music development process. Biped is now available on PS4, Nintendo Switch and Microsoft Windows.

The Early Stages

This game was first born as a physics-driven mini-game, in which characters were made from simple building blocks to highlight the game’s fun gameplay. However, the framework remained undecided. The project team showed us the mini skating game which brought us tons of fun and also left a deep, but biased impression on us. This ended up misleading and distracting us from our original plan. Thankfully, we did two things when everything was still unclear: We made lots of attempts on the game’s musical style and agreed on the main motif of the music.

We took all music styles and elements into consideration by a simple standard—it must be fun, enjoyable, and stylish. With that in mind, we got in contact with the composers we’d been working with and encouraged them to share their thoughts. After trying various ways (including band improvisation), we eventually found what we wished for. We received some cool concepts and music pieces, which led us to find the main motif for ourselves.

As game development progressed, some of the in-game scenes were created, and the game’s initial art style was set in place. To match its art style, we discussed this with the game’s composer, Thomas Parisch and agreed on a more tuneful choice of instruments and music style—a mixture of electronic music and jazz fusion. We also decided on a couple of major instruments—Double Bass, electronic arpeggio, flute, and piano.

Building the Style

Now that we already had a clear direction, our project team didn’t want the game to cater towards either hardcore players or younger generations. The producer, Unisonar’s Vivita Zheng, wanted the music to be more cinematic and complementary to the game’s narrative. Later, the narrative was developed for the game—the robots came to Earth to repair their universe navigation system. Settings such as forests, valley, snowy mountains, rivers, ruins, and other locales were also confirmed. Compared with the mini-game we played earlier, the game setting was given a complete overhaul. We then rechecked our soundtrack to make sure the keynote and style were up to standard.

Eventually, we got a hold of two copies of Thomas Newman’s album, one of which was the original soundtrack from Wall-E, the other one was from He Named Me Malala. These soundtracks combined world music with electronic music and served as a transition between the narrative and various scenes. They helped us answer two questions: 1) How do you integrate music with the in-game environments? 2) All of the in-game facilities conveyed a cold, sci-fi feeling, which was a far cry from the map’s art style. How should the music be attuned to such a change?

In order to solve the first problem, we added a large portion of the in-game music settings to world music—to add a sense of traveling and off-set the backdrop from the story-telling. Although the game’s art design and story didn’t give any instructions, we conducted a preliminary segmentation for every scene—for instance, introducing Indian elements to the forests, Aztec elements to the ruins, Scottish Highlands to the rivers, and the Far West to the valleys, etc. In the recording process, we tried almost all the instruments that came to mind, including the electronic wind instrument, Irish tin flute, Indian bansuri, Slovenian fujara, Chinese bamboo flute, as well as dozens of drums—Scottish bodhran, African udu, djembe, and Latin percussions, etc. Musicians contributing to the score include Brian Kilgore (percussion), Pedro Eustache & Zac Zinger (flutes), Yoon Lee (bass, guitars) and Parisch on electronics, keyboards.

Another thing worth noting was the proportion and characteristics of world music. If the game is dominated by world music, it will convey a more realistic sense to players, which was the last thing we wanted to see. Therefore, we retained a decent proportion of electronic music and carefully managed the balance of world music as well as its presentation.

The second problem lay within various sci-fi facilities found in levels, especially the ones with colossal, notable contraptions. To align them with the music’s style, we set electronic music as the leading tone in these parts, giving prominence to the magic and fun of technology. Therefore, we managed to set it apart from world music to continuously provide players with fresh music experiences and keep the game engaging. This philosophy also divides the game music into two categories: 1) Travel Music (for narrative, scene contrast) 2) Challenge Music (for contraptions and big puzzles).

Pacing of the Game

After solving these problems, we found that the game progresses very slowly due to its unique control pattern. In addition, it was not challenging and rewarding enough to keep players engaged, especially in hard challenges where players would more often get impatient. The project team tried to fix this issue. All while looking for a solution in the game’s music setting. The first thing we did was review our previous music design. What was fun about this game? The game’s current complex controls made it almost impossible to speed up its pacing. So what role should music play?

With that in mind, we replayed the game and didn’t get a breakthrough in pacing. Every action needed to be performed step-by-step, but was its slow pace worth digging into? There were 7 primary levels in this game, each having a unique playstyle. Though the gameplay was slow-paced, levels were distinctive. For instance, the first level required players to walk through a series of red and blue floating panels, each player having their own color. Should the player step onto the wrong color, the panel will disappear and both players will fall into the valley.

It’s a challenge set to test the coordination between two players. Is it possible for us to highlight the rhythm of their careful treading? In the second level—the balancing level—players swing up and down on a seesaw. Can we regard the swinging as another form of rhythm? After categorizing all the levels by this rule, we found that they can also be classified by the robots’ actions, which opened up a new horizon for music design. For instance, we could use a shuffle to imitate their unsteady paces, using a slow waltz to convey the enjoyment on the seesaw or the fluidity of drifting.

We made a new batch of soundtracks with these unique rhythms and significantly livened up the game experience. Parisch integrated the unique rhythm and elements of every level into its original music style, thus creating a one-of-a-kind musical genre for our game.


In terms of rhythm, we also considered a more complicated approach—to switch music according to a player’s skill level. There was a total of 3 skill tiers—Rookie, Normal, and Good. A player’s skill tier is set as Normal by default. If they’re stuck in a level for a long time, challenge music will be shifted down by one tier; if they’re still trapped in the level, music will be further shifted down to the current level’s world music. If the challenge remains unsolved, music will fade out for a short period. On the contrary, when a player plays well, music will be shifted up by one tier and become more intense.

Later we found that a player’s skill level can be easily identified by the time it takes them to complete a challenge, which means music can also be sorted by time from high to low intensity. If a player is highly skilled and swiftly completes all challenges, music will remain at high intensity, which makes gameplay more exciting. If a player stumbles forward in the game, he can still experience a rich variety of music and not feel annoyed by its repetitiveness. The advantage of this approach is that programmers don’t have to spend more time tweaking the game’s current settings.

Unfortunately, this approach was not adopted, principally because the difficulty of the game’s later levels drastically declines, so players are less likely to fail in a level. Also, because re-editing and re-organizing music demands a great deal of time and effort, yet our time was limited.

There is no “best,” only “better”. Game development never runs smoothly. Likewise, all music designs must go through a painstaking period—the early preparation and mid-term review are particularly important. During the development of Biped, we had a very limited time in postproduction to polish up some of the details, which was a lesson learned. I keep a record of these ideas and experiences in hope that our future designs will draw inspiration from this.


When discussing the overall collaboration on Biped Koozer says, “I wanted to give a very special thanks to Thomas Parisch, our excellent composer. These difficult settings were all realized in his hands. Thomas and I have been working together since Iris Fall and have established mutual trust, along with excellent communication. From the transformation of musical instruments and experimental sounds in Iris Fall, the fusion of different styles in Biped, the use of musical structures and the creation/manipulation of sounds, Thomas’s very high level of professionalism, incredible imagination and creativity have brought us a lot of very nice surprises. The whole composition process was full of challenges, but we found common goals in continuous exploration, inspired each other all the time, and finally completed the composition of the whole project perfectly.

You can listen to the Biped score here.

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