I played it through and had a blast! I found myself immersed in your game, it gave me an old "Alone in the dark" vibe that I loved. The corrupted version of the house is a very nice touch when you are back from the mirror world. This amount of settings and polish is commendable.
I found movement very smooth and enjoyable, I had occasional cursor bugs (it would stay "?" for a while), the mini map didn't get updated right after teleporting to a new location, or the gun would sometimes clip through the decor, but nothing major.
Sometimes I had the impression that the grid wasn't always square, for instance when moving from a room to another, it felt like the character took more than one step. That made interacting with some elements a bit more complex, like the spheres you have to stab from just the right angle in the mirror world. It didn't prevent me from enjoying your game a lot, though.
Great work!