Hello ! We had a fun game yesterday with a group of friends. They incarnated a group of credule gas creature (wearing membranes, to avoid constantly mixing with each other), which have been convinced by the dominent sentient specie from their home planet to move away (because it would be "such a nice trip").
As an extra game play mecanism, we used Andrien's idea (post below) to settle population (the blue cubes, on his shot). And after that, we used a mecanism similar to Lay Me Down to play the evolution of the colonies over a few centuries.
It has been pretty chaotic but fun.