Every act-cycle represents a time step. In each time step, a living cell dies if it has 0, 1, 4, 5, 6, 7 or 8 living neighbour cells. A new cell is created if it has exactly 3 living neighbours. You can read more about it here: https://en.wikipedia.org/wiki/Conway%27s_Game_of_Life

Cool thing, it reminds me of one of my simulations :) Did you do it on purpose that the reproduced creatures spawn randomly and not at the parent's location?

Interesting thing... If you are using Windows, click "Win+D" twice. This will close and re-open all windows. You can also try to open it from the Downloads folder (or where you downloaded it to).

Hm, I can't start the game here on the site. I get this error: UnsupportedClassVersionError greenfoot/export/GreenfootScenarioViewer : Unsupported major.mino version 52.0 It works when I download it though.