What about inviting your opponent to a duel which you are going to do at the rooftop? This duel will be done by assassin rifles. It will not be enough for you to hit your opponent, also you should push your opponent from the roof with your shots. The player who pushes his/her opponent five times wins the game.
Player 1:
Jump: "W"
Shoot: "E"
Player 2:
Jump: "I"
Shoot: "O"
Have fun!