Frontline Commando backup & Restore (FLC.BR) backup your game progress on external storage without rooting your device.
Imagine that you've got a price during the 15th day lucky draw or you played a several months' progress but found the save is crashed on someday, it is a nightmare.
Backup the progress and you will have a snapshot or restore point.
You can even copy the backup files to another device then restore them. So that you could continue the progress on another device or even you are switching to a new android phone.