I just finished playing this for the first time. (I got the happy ending! Yay!) Now I have to play it a few more times to get the other ending(s).
(I didn't get all the photographs, though, so there were 2 numbers I didn't know for the passcode. I'll see if I can get them all in the next playthrough.)
In summary -- this is beautiful. The graphics are so simple yet evocative, haunting, and the interplay of childhood memories and adult experiences creates an atmosphere that alternatives between terror and eerie anticipation, that feeling of waiting in the hush before the storm. Then, it becomes ... welcoming? A feeling of being at home.
This is a tour de force. For such a small game with simple mechanics, it made me emotional.
* Plus: Nika is so cute! Must protect!