This was a REALLY good concept for the theme, I liked it a lot.
I do think you could change the mechanics of the black side, possibly have a shader of "remembrance" rather than just black. So the player can see what they have seen but it slowly fades if you don't look back and nothing new is displayed so you can still get hit without knowing they are coming.
This way it would improve the visuals of the game and make it much more engaging rather than the big black box on the screen XD