Lightless (RedBerylFTW)

Lightless is a Psychological Horror Point and Click adventure game.

2050: Downtown Manhattan has sunk beneath the surface after a nuclear bomb explodes underground. A small group survives the catastrophe, but one morning protagonist Avery wakes to find his group has left him behind with no supplies. Avery's only hope for survival is to ascend to the top of the ruins using whatever seemingly useless item is at his disposal, all while his mental state is deteriorating.

No known full release, no known demo release, but there is a tech prototype built that's available for download.