First person, mouse to look, W A S D to move, E to interact and F for the flashlight. There is no tutorial past the control list on the title screen. There is an island, generated rather than modelled, with water, terrain and objects that are all being worked out as you look at them.
What you do is explore, find the things that are findable, and work out what the island wants. It saves, it has a run button, and it has a quality setting for when the machine starts complaining. It was written for a competition with a thirteen kilobyte limit, which is worth knowing only because it explains the strange, dreamlike smoothness of a world with no textures in it.