CellCraft is a biologically-accurate real-time strategy game and you can play it online and for free on Silvergames.com. You start as a very lonely single celled organism. Follow the instructions of a mysterious creature talking to you. This game explains to you in a lot of detail how cells work and it names every part of the cell by its scientifically correct name. That means you can learn a lot about yourself and biological processes in general in this game.
Grow and become stronger. For example you have to collect molecules that the cell needs to survive. Create life in the smallest way possible. The mission of CellCraft is to build a cell, fight off viruses and save the Platypus species!