The options menu can be accessed from the Background screen of a new game or the System tab during a game. It controls the gui, events, etc. The top area of the menu will explain each option as you hover your mouse over it. Most of the options are self explanatory.
The option that needs more clarification is:
- Bad Ends: This option will enable/disable game overs. For example, the bad Milking route will result in a game over if this option is enabled or turn you into a dickgirl if it is not.