Nothingness: Ground breaking? What about a machine gun wielding number 1? dAGGER would like this too as it could all be over in a couple of moves :)
My vote is for atomic espionage, extinction espionage, the canon piece, the 3 game match and the 4 player individual (in order of ease of implementation).
(hide) If you want to play a game with an opponent of a similar level, you can define a required BKR range for a new game invitation. Then nobody with a BKR outside this range will be able to see/accept it. (Katechka) (show all tips)