Install freeciv-client-gtk3 by entering the following commands in the terminal:
sudo apt update sudo apt install freeciv-client-gtk3
Description:
Civilization turn based strategy game (GTK 3 client)
Freeciv is a free clone of the turn based strategy game Civilization. In this game, each player becomes leader of a civilisation, fighting to obtain the ultimate goal: the extinction of all other civilisations. . This is the GTK 3 version of Freeciv. It is recommended to install the »freeciv-client-gtk« package and to use the GTK+ client unless you really want to try this one. The GTK 3 client offers a different look&feel and is still under development.
Homepage: http://www.freeciv.org/
Version: 2.5.10-1
Section: universe/games