Alarms are abstract game elements that provide information about particular game state changes.
Alarms are turned on and off either by manipulating explicit game elements or by inherent actions of the game elements. Alarms can, for instance, show if a forbidden area has been entered or if a certain game elements have been manipulated.
Some team-based first-person shooters, such as Return to Castle Wolfenstein: Enemy Territory, include Alarms to inform the players about events that are relevant on a team level, e. g., that a particular goal has been completed or that a certain activity has been initiated by the other team.
Using the pattern
The main design choices for Alarms are how they are tripped and what Outstanding Features they set off. Further when designing Alarms, the designer may choose either explicit Tools or Controllers to manipulate the Alarms or to have the manipulation of the Alarms as Privileged Abilities for certain types of Avatars or Units. Using Tools or Controllers increases the complexity of the game by allowing such possibilities as deactivating the Alarmwhen it should not be deactivated, Bluffing by raising erroneous Alarms, and preventing the raising of Alarms by destroying the means to activate them. All these actions increase the player's Freedom of Choice but may make it more difficult to guarantee the coherent Narrative Structure of the game. Having Avatars or Units with Privileged Abilities to raise Alarms may avoid this problem but may break the Consistent Reality Logic.
The activation of the Alarm can signify the failure of a Stealth or Reconnaissance goal but can also make the completion of it more difficult by imposing a Penalty. This Penalty is often a Time Limit, the introduction of new Enemies, or directing existing Enemies to the area where the Alarm was raised.
Of course, the pattern can most easily be deigetically be presented as its namesake.
Alarms are ways to pass information about activities and states within a game, and as such provide a Game State Overview. When activated by players, an Alarm notifies the players that they have been detected, and this can explain changes in the behavior of Enemies or the introduction of new Enemies within the Consistent Reality Logic of the game. When activated by others, Alarms can notify players of Enemies activities. In both cases, raised Alarms cause Disruption of Focused Attention.