Just start a new game and pick Nightmare!
Your bonuses are only kept if you start a new game immediately after finishing one, so if you open the game and pick start a new game, you're fine!
Good luck!... a pure nightmare with no pinkie is a living hell!
![Fear +::fear](./images/smilies/55.gif)
Hence why it opens the Gates of Hell world!
![Big grin +::biggrin](./images/smilies/07.gif)