The 'sound is your sight' concept is one of those design choices that sounds simple but has massive implications for how tension actually works. Horror leans so hard on visual scares - darkness, jump cuts, monster designs - and stripping that away forces the whole thing to live or die on audio alone. That's a bold call.
What I'm curious about is how you handle spatial awareness. Are players building a mental map through echoes and footsteps, or is it more abstract? Games like Blind Drive went the abstract route and it worked really well, but a grounded horror version of that could hit completely differently.
Also - solo project on something this concept-heavy is genuinely impressive. Audio-first design has no safety net. If the sound design isn't there, the whole experience falls apart. No visuals to cover for it.
Adding this to my list.