The Tankies doesn't require any Android permissions. Thus, there is no advertising. The app can be operated offline The 'Tankies' App stores EACH valid action of user, automatically, to internal storage. Thus, you don't have to care about saving at all.
It's safe to download the app. Obumo_de is the developer of Tankies that refers to the Board Games category. Over 10 users downloaded and installed the game and its latest release was on Oct 10, 2020.
This application has the average rating 4.5 on Google Play. Download the installer of Tankies 2.4.44 that is provided for free and have a look at users' reviews on Droid Informer. The app is built for Android 4.0 and higher.