You can reset the game's settings by deleting the settings file. On most Android devices, it'll be located at a directory that looks something like:
To access this, you will need to use a file explorer app, such as ES File Explorer, or a computer and USB cable connected to your Android device.
Deleting this should reset your game settings to normal/default (but will not remove your save files). If you're concerned, you may want to back it up somewhere by copy-pasting it before deleting the file just in case.