By registering with your Apple ID if you have an IOS device, or by registering with Google Play Services if your device is Android, you can enable the “Achievements” section. By doing so, you will be able to find there all the information about your plays, levels and completed episodes.
You will be able to register to enable it by accessing the Settings menu from the upper left corner of your screen, tapping on the green button with the text "Register" which is under the "Support" option.