So what is the story of Dear Esther? In my hours of drifting over (and under) the rocks, I came up with several.
My imagination was truly allowed to run riot. There were things which made coherent sense, punctuated with contradictions. It didn't matter. The point is to approach it with a child's idea of asking questions, checking things out, just looking to see what's over there.
But the ending does consolidate enough to give you a more definitive conclusion. You are left musing, but not in limbo anymore.
Or did you mean reality, then it's apparently students at the University of Plymouth coming up with a concept. Ordinary investors made it happen via contributions to The Indie Fund.
Within five and a half hours, they had made their money back. It has remained one of Steam's most popular games, since its release on February 14th 2012.
Dear Esther was originally a mod for Half Life 2, but it out-grew its conception to fly in its own right. You don't need to have played (nor even heard of) Half Life 2 to enjoy it.