Heyo! I gave it a go, and here are my thoughts so far:

There are several spelling errors that should be addressed, as they cheapen the experience.
Voice acting would be nice.
Having an idea as to where to go would be nice, but is not necessary. However, I had trouble using the action command, so perhaps a reticule that shows up when you are near an interactable object is something to consider.
Perhaps changing the story a tad, as the timeline of your reasoning for the main character seems out of place (I.E. your brother-in-law shot his family, and then himself according to the "police report", yet his head is actually in the house)
Some music for the "boss battle" seems appropriate, as well as indication as to whether your bullets are connecting with the demon would make everything a less awkward experience.

Hopefully you are open to this constructive criticism, and I hope to see the finished product!

Here's my Let's Play of the whole thing!

https://www.youtube.com/watch?v=gerJR73WWgA&t=25s