I feel like this is the same game style as Crypt of the Necrodancer, but I haven't played that game, so your getting 5 stars for innovation anyway.
My biggest complaint is that the game in unplayable once you reach <4 health. if you're not already next to some health, that's pretty much a death sentence since you can't see anything.
The atmosphere was likely exactly what you were going for; scary, intense and panicky. The game has a good pace, forcing you to constantly run into the unknown because staying still will kill you. The oppressive circle of darkness was also quite well done. I would not have thought to put purple particles circling around it but they actually work pretty well.
The great atmosphere is marred somewhat by the enemy's color pallet. I understand not wanting to make the pure black as they would blend in with the rest of the darkness, but making them a light grey is just not as intimidating as the rest of the game's empty darkness.
Last note: Some people see an installer and immediately decide it's not worth the risk that your game is a virus. If there is a way you can distribute this game without using an installer, that might help you get more people to play your game.