It's a cool idea, but in the world of free to play shooters, $10 for a concept that I'm unsure would work seems risky. I'm not saying it isn't worth $10, but I would for sure at least give it a shot if I could try it for free at least.
Multiplayer-only is a death wish. Either you succeed instantly and massively, or your game is nonfunctional. With digital distribution it's not even a coaster.
As to the game itself - proprioception, people! Have some particles in midair to show when and how you're moving, even when you can't see shit. Have the tiniest fake light for your immediate vicinity, because that's the only way to convey onscreen that your guy is rubbing his face against a wall.
I'm reminded of a struggle I had with The Long Dark trying to do basic things (like find a bed in a cabin) in the pitch black dark. IRL, when in similar situations, I could feel around, and had no problem figuring out where up and down were, which is a problem without a field in first-person games.
I suggested a slight gradient in absolute black to indicate poles, or some other kind of artificial horizon, but they said no.
Hopefully it does well! They must be so excited to be working on their own IP. They’ve worked on plenty of solid and successful games so they’ve had plenty of experience.