(warning: spoilers)
I'm always suspicious when it comes to these atmospheric games, so I guessed that a few scary faces were about to appear out of nowhere- especially the bathroom camera tape! Nonetheless, I still probably need a change of clothes.
You completely nailed the atmosphere, just like the Silent Hill games, but at the start where Adrian is shouting for help, the repeated phrases just got annoying, even more so when you realise when he has been doing so for a couple days.
The clues/ passwords need to be a little more obvious, because your common player isn't exactly Sherlock Holmes. Unless the player has already played the Silent Hill games, they won't know to check everywhere, even if they were previously told there was nothing there (for example the magically appearing key). Also, the important objects in the Silent Hill games are slightly shiny or made obvious somehow.
Something that ruined it for me somewhat was the fact that the bodies of Adrian's wife and son were covered with a sheet, but it was almost as though they were placed there, and I assume that zombies haven't got much respect for the dead, much less feeling compelled to cover them in a sheet in a protective manner after brutally murdering them and cleaning up the bloody smears over the walls before they leave. This made Adrian look guilty as soon as you see the bodies, and all sense of the presence of zombies was lost- but I understand that this was necessary to make Adrian look guilty, but making the scene look more careless/ brutal would have done nicely :)
Sorry for ranting :) Don't get me wrong, this game deserves a high score, I was just trying to point out things that could be improved :)
To those people who say "TL;DR", don't read it if you don't want to.