Wooah, back again!
New Feature-rettes
Enable FrotzBot for private messages (at your peril! 
)
Allows users to play in private, but usage will be less transparent. If you have a big enough server this may not be an issue for you.
https://github.com/merefield/discourse-frotz/commit/cf8c459307c50adeb4f7eccd39071bdf076dfdc9
default: OFF
If (s)he is not enabled there, the user will get a polite message:
Restrict to a list of Categories, or allow all:
https://github.com/merefield/discourse-frotz/commit/b621c91f9e145d4511b7d1b649c10f3044ceb356
default: ON for all Categories