Imagine Nations is a sandbox game that defies genres by allowing you to play the game using the features that interest your play style the most. Once you’ve created your character, you are dropped into a voxel universe (think games like Minecraft and Cube World) that will let you do as you please, for better or for worse. The center of Imagine Nations is the various cultures that can be found on planets throughout the universe. You begin in one of these towns, with a culture that looks similar to yourself. These cultures act with or without your input, growing from humble beginnings as hunter-gatherers to massive empires spanning a galaxy filled with space-age technologies. You are free to support the towns directly through various means, or let it grow naturally.
This video highlights the day and night cycle in Imagine Nations with Unity5.