Basic version
In an assassination game the players hunt each other and strive to get into a situation where they may apply to each other the playful mock guns dictated by the rules. The game's base format is the so-called murder rings, where the umpires arrange the players into rings: Player A's goal is to assassinate Player B, Player B is hunting for Player C, and so on, until Player N hunts for Player A. If the Player A manages to assassinate the Player B in manner allowed by the rules, A and B shall contact the umpires and tell their own sides of the story for scoring. After this, Player B is dropped from the circle and gives their target, Player C's, information over to Player A, who starts hunting for Player C.
If the game progresses like this to its logical conclusion, two last players standing are hunting for each other in the end. This is rare, however, and most often game is played until a pre-determined time limit and the winner is decided by points.
Different variants of the basic version can be found from the international colleagues of HUSH and the book by Steve Jackson, "Killer, the Game of Assassination" (Amazon.com product page).
Time and location
The game may be restricted to a certain place and time, e.g., one afternoon and a certain park, but the game can also be played for several weeks, during which the players try to live their normal lives knowing that somebody is stalking them all the time. In the process assassins try to recover free time of their own to gain a time slot and a shot at the murder of their own victim. In a long game it is usual however to agree on safe zones and times, where the game is not on and the players can safe from ambushes for a short while.
The umpires
The umpires make the decisions about the rules, maintain the game, resolves the issues risen during the game, work as inter mediator in the fights and scores all the acts. The umpires may choose to end the game, if they see fit (for example, if the game has become stuck in a situation, where three players are spending their days hiding in their basements in utter terror).
Players' safety, privacy and bystanders
The rule number one for the game is common sense. Getting murdered may well be surprising, so it is plainly obvious from the start that people are not disturbed when, say, they are lifting heavy objects or operating heavy machinery. The participation to the tournament means that the player is okay with the small violations of their privacy (since the assassination usually requires stalking), but most rule systems (also HUSH's) emphasize the physical immunity of the players. Pretty much any serious rule systems also dictate the bystanders to be absolutely pacified from the murder attempts: the purpose of the game is not to cause disturbance to those who are not involved in it.
