I haven't read the rules yet, but I'm in.
EDIT: Okay, I finally read the rules. Nothing seems broken per se, but there is one very troublesome aspect pertaining to Cube the Suicide Penguin. I don't like the fact that if he gets voted off, everyone who voted for him dies too. It's going to really discourage people from voting until he dies. Hell, for the first couple of days I'd just vote for myself rather than take a wild guess and rick voting for Cube. It would make a lot more sense to have it so only the last person who votes dies (like the last game).
Also, I'd like to clarify ... unlike the last game, Cube can choose two people to die at any time, not necessarily on the third day, right? And he dies too, no matter what (he doesn't live if he guesses a mafia member like the last game, right)? It just doesn't seem like he'd ever want to kill anyone. Man's natural instinct is self preservation. Why would he choose to take himself out (and a couple other people) if he thought still had a chance of living another day?
Finally, I don't believe you specified how many mafia henchmen will be on each team.