Wayward is an in-browser roguelike RPG implemented in HTML5, where the player character starts on an uninhabited isladisland. He has to survive and find treasure.
This is easier said than done. You'll have to use your wit, plan your moves and craft many, many items in order to avoid starvation and dehydration, fend off bears and monsters and maybe finally get off the island.
As is common in roguelikes, the game generates its content randomly, is turn-based and quite complex.
Playable for free at http://www.unlok.ca/wayward/