2 things:
1) a "main menu" button would be good instead of having to fully quit then re-open the game to change settings
2) having settings save instead of resetting every time you open the game would also be good
A option menu for in game is on the list and will be added hopefully for the next update :D
If the default settings are replaced every time when you start the game, it could also lead to work. I dont know if this is handy.
