Mafia 69. War of the Elements.

It is allowed to reveal one's role and also to share the results of all nighttime actions.

A bad rule, a very bad rule. It leads to all roles being revealed on the very first day of the game. With this rule and the given number of Mafia and Serial Killers relative to the town (there are many townspeople), it's a foolproof strategy – everyone just reveals themselves and starts eliminating players.