watched all,no clue. definetly an ARG because the youtube links back to the dev here
okay so my interpretation of the story so far is this:
guy gets haunted maybe either literally or mentally,and has trouble sleeping. maybe theres also some sort of cult involved because of the whole "we are happy people". maybe put the audio from the first three into a spectogram or something/similar or slow it down,but i have no idea where to go from there if theres nothing in the sound. maybe wait on updates since its listed as in development
For me, especially after reading the police files below the first game, I think the creator lives near the forest where a crime occurred at one of the children's camps. The children were likely victims of some kind of cult. The creator either lives near the forest or is connected in some way to this case – he's in the cult or one of the investigators, and is now being haunted by a demon or demons that arose from these children.
The sun could refer to the children's memories – the last thing they saw was the sun or the warmth of some light, which would explain why they ask if it was really the sun.
Or the cult could actually have something to do with brainwashing people with this line.
In the video with 'the sun' – faces – we can see seven children in full view – who would represent the victims depicted in the police files – but there is an additional eighth child who (at least to me) strongly resembles the monster chasing us in the first game. There's another issue: Who was recording the video with the camera (I think)? - Wish - we can clearly see that someone is recording it - it's probably the main character - but this leaves us with another question mark - who was our creator for this?
Sorry for the bad English and some oddly worded sentences - I'm not an English speaker :)