You take millions of footsteps in video games and the sound accompanying those movements is probably something that becomes white noise after a while. There's a good chance that won't happen in The Witness though.
In a post on The Witness blog, creator Jonathan Blow reveals the kind of small detail that shows an intense focus on creating a sense of place:
Q: How many footstep sound effects are in The Witness?
A: 1119 so far. They sound really good! We will probably be in the Guinness Book of World Records as the game with the most footstep sounds…
Blow elaborates on just how that specific number comes about in the comments:
We have different sounds for left and right foot, always. For any given material there are 5-6 variations for each foot, to avoid mechanical-sounding repeats; let's just say 5 is average.
So for walking on one material, you have 10 footstep sounds minimum. Thus 1119 sound effects would be about 112 materials to walk on.
But actually, it's fewer materials than that, and more footsteps. We have reverb footsteps for specific locations, where we blend reverb in and out, or crossfade between two reverbs, depending on where you are in a room or hallway. We also have "texture footsteps" that are meant to be layered onto a base sound… so if you are walking on grass, but a little bit of dirt is poking through the grass, the game will play the grass footstep, but with a little bit of dirt texture overlayed on top of it. (The loudness of the dirt texture sound will be scaled by how much dirt is poking through the grass).
The reason behind all this is: The Witness is a game about you wandering through a deserted island. You are the only active character in the game, so the sound of your own motion is hugely important for establishing setting and mood.
The guys at Wabi Sabi sound are doing all this work. It is coming out very well!
When will you get to hear the other shoe drop in The Witness? Not for a while, as Blow says that there's much more work to be done. As for the Guinness Book of World Records, there have been far more dubious achievements between those covers.