While a lot of specifics are missing there are enough hints to form the basis of the story and apply them to fill in the gaps. Esther died in a car accident. The cause is left vague as at one point a drunk driver is mentioned while the paintings of the wall are schematics (some are chemical symbols for alcohol) for a cars brakes. It's never made clear whether you were the person responsible or a loved one of Esther. Anyway you are overcome by her death and eventually kill yourself, or at least that is what the majority of the narrative hints at. There are clues that suggest you died in the crash too.

Add on top of that the hints of the player being in hospital with kidney stones and that's why Esther was travelling along the motorway. Hints of Damascus and the conversion of Paul from the bible suggesting that during grieving the player found religion so believes there is another life which is possibly the island or another heaven as he soars away like a bird at the end.

There is so much more there. Granted some of it you would need to discuss with other people to understand, like the schematics, but it is there if you look for it and give in to the puzzling storytelling. Only the essential pieces are given to you the rest you have to gleam from what is said and the items you find.