So creepy, but also so cool! I love how unsettling a lot of the elements are together. Like that version of "Let Me Call You Sweetheart" playing. (Who is that, btw? I don't recognize that version.)
A few minor UI elements would help, I think. An aim cursor, ammo remaining, score. Stuff like that.
Would NOT have thought of taking it in a 3D horror direction. But you did it and it works really well. Nice job!