So the way this game starts is: You crash on a ringworld.

You have none-to-very-few implements to start, and you mostly have to eke out a living in the general wilderness you find yourself having crashed in.

Eventually, you find a settlement.

Nobody speaks your language, but the language is consistent and comprehensible after a while.

Eventually, you can hire people to hunt with you.

At each major step of things, the interface changes.

When you start, it's an FPS.

When you get a grasp enough of the language and the locals, you have the option to switch to a turn-based tactical interface. You can switch back and forth freely.

Eventually, you might have a home in the town. You can play the game this way forever if you want.

OR

You can go further.

Set up a coup and install yourself as leader -- or make your own town, out in somewhere wild?

You unlock the Civ-style interface.