Much like the original Hellblade, Senua's Saga: Hellblade II is a narrative action game that puts players in the perspective of Senua, a traumatized Celtic warrior with psychosis. As a game about learning to see reality and Senua's visions as one and the same, Hellblade II delivers an experience that utilizes unique visual and, most especially, audio effects that emphasize the protagonist's state of mind throughout her journey.During the 2025 Game Developers Conference, Ninja Theory principal sound designer Daniele Galante gave a detailed presentation on the sound design of Senua's Saga: Hellblade II, and how the original game's innovative use of binaural audio was expanded for the sequel. In addition to breaking down how actors performed their sessions with binaural audio setups, the sound designer explained the challenges and benefits of heightened sound design for games.Creating a hallucinatory soundscapeDeveloper Ninja Theory has built quite a pedigree for crafting games with rich visual styles and impressive sound design. The original Hellblade received significant praise for not only being a game with a modest budget and scope but also for how the developers managed to push their resources to produce a visually stunning game with stellar audio design and clever use of binaural audio audio design that re-creates sound within a 3D space.Related:For Senua's Saga: Hellblade II, Ninja Theory received more resources and a larger team to make a more high-end follow-up, and the sound design was one area that the developers wanted to improve upon. Throughout the game, Senua battles foes from rival clans and other unsettling foesbut her journey is fraught with visual and auditory hallucinations that turn her already dire circumstances into a harrowing ordeal. Ultimately, she uses her survival skills and perception to center herself, and by the game's end, she once again accepts herself and comes to terms with traumas.According to Galante, continuing with the use of binaural audio was necessary as it allowed them to help players get a better understanding of how individuals hear auditory hallucinations and to immerse them within Senua's perspective."Many people think that you hear [auditory hallucinations] inside your head, but that's not accurate." In most peoples' experiences, they hear voices around them, very much like how I'm speaking to you or when we talk to each other," said Galante. "Using binaural audio was an obvious choice because we want to reproduce these voices around the player to get them within this experience. On top of that, we can give our performers a very powerful tool, which is their body language movement. They usually cannot use it when they play video games. They have to stand in front of the mic, which is a powerful tool. They have to fill their performance with more emotion, and because of that, we found that actors with a theater background usually work very well with binaural audio."Related:As Galante explained with several videos in his presentation, the actors playing the Furies (Abbi Greenland and Helen Goalen)the voices that Senua hears throughout the game performed their lines while also moving around a Neumann KU 100 Binaural Dummy Head mic during the capture sessionstreating the mic as if it were Senua and both the player. The special mic simulates the average-sized head and captures sound in a 3D space, but Galante made a point to mention that the effectiveness of binaural audio tends to vary for some people, and he stressed the best way to experience the game's sound design is with headphones.Sound drives story, but story is kingOne note that Galante stressed was that the game's audio design had to serve the storytelling. For Hellblade II, the principal sound designer treated the binaural audio recordings from the actors as if it were an acoustic instrument. The reverb created from the performers' voices and the sound designers adjusting it in post-production with Visual Studio Technology (VST) helped put players in the state of mind that Senua was in.Related:The use of non-verbal voice capture to create eerie noises and other off-putting soundsproved especially important in helping to create an unsettling mood, all in service of Senua's perspective. Actor Edward Spence provided voice lines and non-verbal audio for a sequence where Senua travels through a sunken cave filled with the voices of the dead reaching out to her."Our voice is an extremely powerful instrument, and we should use it more when we do sound design," he said. "We also record nondialect stuff, so any possible noise you can make with your mouth is there because we want to be experimental and take it to the player's brain and make them feel uncomfortable. Because when we hear a voice that is not supposed to be there, that can make you feel weirded out by it."Image via Ninja Theory/Microsoft.Image via Ninja Theory/Microsoft.One of the major sequences in Ninja Theory's sequel was Seuna's confrontation with the Tyrantan emotionally challenging and brutal boss battle against the protagonist's father. To present this boss battle as a sequence where Senua confronts a major source of trauma and abuse in her life, the developers combined the voices of six different voice actors to make the voice of the Tyrant. They utilized the 3D audio effects to give the sequence an oppressive and all-consuming feel.Galante later stated that, despite the massive benefits of binaural audio for immersion, it also presents several challenges. In addition to being time-consuming to produce, extensive post-production work is required to ensure the binaural audio works in the game for general audiences. Most importantly, Galante stated you need to have a clear vision of what you want to do when recording, as 3D audio is set in stone.One mistake the Ninja Theory sound designer made came early into the making of the audio design for the Tyrant battle, and it was because the rest of the team didn't have a specific vision for what the fight would be like. When he revisited the first actor's recording following the team having a clearer idea of how the encounter would play out he found it wasn't quite suitable for the new concept, and he had to do the painstaking process of readjusting the 3D audio, which meant duplicating the track and inverting and altering the sound to make it work for the concept of six different actors providing voices for the sequence.Still, he remarked that binaural audio has tremendous advantages for immersing players in the game. Still, because there have not been many uses in the creative fields, it can be challenging to find a clear vision and roadmap for its uses, but he expressed that it was worth trying and that he hoped more developers would try to pursue it."For now, there's not much documentation regarding binaural audio on the creative side as it's mostly used for scientific purposes and not often in a creative field," said Galante. "So everything we did, we learned by making mistakes, and we did make mistakes along the way. Because of this, recording binaural audio can be quite an expensive part of our job. So what I'm sharing here is our experience, and what worked for us, and is not the rules set in stone, but hopefully, this can help some of you if you want to do some binaural recording [for your games]."