Most popular game. CellCraft. CellCraft. Build a cell, fight off viruses, survive harsh worlds, and Tags: Genes, Molecules inside us. Most popular game. CellCraft. CellCraft. Build a cell, fight off viruses, survive harsh worlds, and Tags: Genes, Molecules inside us. CellCraft is a realistic cellular simulation that challenges players to learn about and manipulate a cell and its various components in order to survive.