Freeciv 4

Freeciv is a Free and Open Source empire-building strategy game inspired by the history of human civilization. The authors goal is "Cause civilization should be free!" The game commences in prehistory and your mission is to lead your tribe from the stone age to the space age...
Conversion the regular software to portable requires extra steps:
* Download the installer and extract to a folder of your choice.
* Delete $PLUGINSDIR and [NSIS].nsi.
* Move all subfolders inside the $_OUTDIR directory to the root folder, then delete $_OUTDIR directory.
* Launch civclient.exe.