How does game saving work?

[AC Question]

I recently got a new phone and didn't synch everything over except my contacts. I assumed that all my mobile games' save data would be saved by my Google play account, making it so my progress would be the same once I signed into my account on the new phone. But I signed in, and I'm not getting my saves back. I'm back to square one on everything. Does save data save to the device or is there a different way to get my data back. Btw the other phone has been sent back to the manufacturer and had a factory reset already.

 

[dpham00]

If it is on marshmallow and the app developer set up the correct settings then the app data would be saved to the Google account. However if not on marshmallow then the app data isn't saved.