Sacred Haven of Debauchery

What's unclear about my clearly described rules?

There's a mafia game (regardless of the genre) where it's clearly stated what you can and cannot do. The player is given a role with specific actions and character traits. The goal: defeat the opponents and win. Everything is clear, concise, and understandable.

Then there's an expansion where you have to come up with something, and it must be "consistent with the GM's world" (where is it stated what is consistent and what is not?). If you're using worlds from some of your games, then I'm completely out of it: my "world" is limited to FM 2008 and the first parts of King's Bounty. The goal is unclear, and it's unclear what to do.:confused: