The latest Hellblade development diary shows us how Ninja Theory aim to hook players into the world of Hellblade with binaural audio, which is basically a way of recording sounds with microphones that mimic human ears. There is literally a microphone with ears in the video. It's worth watching just for that.
This special recording technique is particularly useful to portray the hearing of internal voices, which is perfect for a game where the protagonist is suffering from mental health issues.
You will obviously need to wear headphones to make the most of this effect, however. In fact, put your headphones on now and watch this video to get an idea of what to expect:
It's a cool technique, and the video - particularly the bit near the end where the guy whispers into the mic - really makes you begin to wonder what kind of creepiness the sound will produce in a game tackling such an untapped subject.
Hellblade is set for release sometime in 2016.