affordance: A feature of an object, the “what it lets you do.” For example, a window may be defined by its physical characteristics (height, width, etc.), but it can also be defined by the fact that it “affords” us the ability to see from one room to another while retaining a physical separation. In terms of games, a console's controller affords us the ability to give many differentiated inputs to the system, a monitor affords us a visual representation of the game state, an avatar's controls afford us the ability to influence the game state, and so on.
binary space partition (BSP): A way of describing the associations between objects to be rendered in a game engine, analogous to an index in a book. Rather than render every object and potentially do unnecessary work by rendering objects that are obscured by others, the BSP table can be consulted, redundancy can be avoided, and the rendering process can be speeded up.
boss: A boss is bigger, smarter, and harder to kill than other enemies or monsters. It is normally met at the end of a level and has to be defeated to pursue the journey.
deathmatch: A form of multiplayer gaming where all the players are pitched against each other. The winner is usually either the last man standing, the player with the highest number of kills within a time limit, or the first player to reach a preset number of kills. Team deathmatch is a variation that adds cooperation between players and is the basic model behind the overwhelming majority of multiplayer games and game modes.
diegesis (diegetic/nondiegetic): The world in which a story takes place, made up of everything that the characters who live in that world can experience. For example, the music played by musicians appearing in a film is said to be diegetic and can be heard by the other characters in the film, while the film's soundtrack and credits, which the audience sees and hears but the characters cannot, is said to be nondiegetic.
first-person perspective: A perspective that shows the game world as if seen through the eyes of the player character.
first-person shooter (FPS): A genre of action games defined by the direct mapping of the player's perception onto the avatars. In other words, the avatar is only minimally represented, usually by a gun or hands at the bottom of the screen, and the player is invited to look “through” the eyes of the avatar. In recent years, this designation has often been replaced with the more generic “first-person game,” to recognize the increase in numbers of games that do not have combat as the central mechanic, such as Portal, Amnesia, or Mirror's Edge.
frag (fragging): Killing, usually used in the context of killing another player in a deathmatch setting.
frames per second (fps): The number of times everything visible on the screen is redrawn to register changes in the game state (monsters moving, missiles being tracked, etc.). A game's fps rate is often seen as something of a holy grail in action gaming, as it defines how responsive the game is and how smoothly it moves. A low fps rate makes play shuddery and unresponsive and is normally caused by an overloading of the rendering capability of the engine and platform. BSPs work to reduce this slowdown.
gib (gibbing): The bloody lumps scattered around when a monster takes a huge amount of damage in one go and explodes (usually from a rocket launcher or similar weapon). This provides a more rewarding visual kill than normal.
heads-up display (HUD): An overlay on the game's action that gives information to the player about the game state. This is normally nondiegetic, although there has been a trend in recent years to integrate the HUD within the diegetic representation. Normal elements in an FPS HUD include counters for health, ammo, armor, and keycards.
ludic: Of a game. For example, we could speak of a game's ludic elements to refer to those aspects of it that directly pertain to its gamelike nature, such as integer-based health counters or control systems. This is sometimes used to distinguish such elements from diegetic ones in order to irritate game studies researchers.
MIDI: Musical instrument digital interface. Rather than sending audio, a MIDI signal sends information, which can be used to trigger other devices. So a MIDI keyboard could be used to trigger a sampler or a sound card. It is best thought of as a method for creating digital audio.
mod: Modification. A new game created by adapting the code and/or assets of an existing one.
monster closet: A small room that is placed in a map but is inaccessible to the player and normally not signposted with a door. It contains a monster (or several) and is triggered by the player moving around the map—normally opening right behind the player. It is a tried-and-tested method for scaring the living hell out of the player but is sometimes decried as an overused and unsubtle design trick. It still works though.
non-player character (NPC): A game world character that is not controlled by the player.
player character: The main character of the game, whose point of view and body is that of the gamer when he or she plays.
port: A version of a game re-created on a new platform. A ported game normally retains most, if not all, of the original game's features. For example, we would describe DOOM on Xbox as a port, as it's essentially the same game. DOOM 64 for the Nintendo 64, however, is substantially different to the original in many ways, and it may not be appropriate to describe it as such.
role-playing game (RPG): A story-based game where the gamer creates his or her character and chooses the specific role he or she wants to play. The gamer's actions and decisions will change and increase the competence and/or aspect of the character, as well as the course of the story.
shareware: Software that may be freely distributed, normally with a request for donations. Shareware is often part of a larger commercial application, with key features, such as saving files, locked.
speedrun: The practice of trying to complete a game level in the fastest possible time. There are different variations depending on the constraints attached to the run (without taking damage, including killing all monsters, etc.).
texture mapping: Assigning two-dimensional images to the planes of a three-dimensional polygon to create the illusion of detailed environments.
third-person perspective: A perspective that shows the game world as if seen through the eye of a virtual camera, showing the player character in the scene.