Modern clone of Civilization games. This is definitely about the gameplay and not the art! Sort-of-shameful admission, I never bought Civ IV, V, or VI. Playing Unciv gave me some insight to those new Civ gameplay concepts people were talking about!

The installation was very lightweight. There were ways to export your save file as a text file for transferring between Android and PC, though I recall a little buginess with that. Maybe keep a few saves.