You don't have to use any if you don't want the only theme you must follow is Cosmic Horror. These are just for people who like to experiment with Secondary Themes.
Just to clarify for anyone wondering that the optional secondary themes are just that optional. You don't need to use any of them if you don't want to, they aren't required. They also don't affect the voting of the game in anyway either. The only theme your submission must follow is Cosmic Horror.
