Design

Active Time Battle is Square's combat system, introduced in Final Fantasy IV in 1991: each character's gauge fills in real time, the character may act only when it is full, and enemies keep attacking while the player chooses. Square patented it in the United States, used it through Final Fantasy IX, and brought the gauges back in Final Fantasy XIII.

Between games, an arcade machine plays itself: title, story, high scores and a demonstration, looping until someone puts a coin in. Period writers called it the machine's sales pitch, and an arcade game could live or die by it. Home games kept the idea as a demo mode, and Atari's home computers used the same name for a colour-cycling screen saver.

Base building is the construction half of real-time strategy: structures that gather a resource, produce units and defend the plot. Reviewers described Dune II in 1992 as Sim City with a war attached and called Warcraft and Command & Conquer copies of it; by 1996 a review could explain a game by saying it had no base-building.

A branching narrative is a story whose path depends on what the player does. Period sources trace it through the Fighting Fantasy gamebooks, adventures with several endings (Deadline had ten), Wing Commander's performance-branched campaign, Chrono Trigger's alternate endings and Blade Runner's randomised suspects.

A crafting system lets the player make items from gathered ingredients. Darklands mixed potions from formulae in 1992 and Secret of Evermore did the same on the Super NES in 1995; Ultima Online and EverQuest turned crafting into trade skills a player could live by, and by 2003-04 reviewers judged an online game's recipes, forges and crafting stations as a game in themselves. Minecraft later made a crafting grid its centre.

A landscape the game edits while you play, so that every crater and tunnel changes the next shot. It came from the artillery game, two guns and a hill, by way of Scorched Earth on the PC and Scorched Tanks on the Amiga; Lemmings made digging a puzzle, and Team17's Worms (1995), whose levels were 960 by 350 pixel pictures, made it famous.

A dialogue tree offers the player a short list of things to say, and each answer opens another list. Accolade's Law of the West built a game on four replies in 1985; Sierra swapped its text parser for a "conversation tree" when it remade Quest for Glory I; LucasArts used trees for jokes, and Fallout and Planescape: Torment tied the options to the character's statistics. BioWare's Mass Effect later turned the list into a wheel.

Difficulty design is the choice of how hard a game is, for whom, and who gets to change it. Arcade makers tuned it to the coin: "easy to learn, hard to play". The Atari VCS put two difficulty switches on the console, Compile's Zanac adjusted itself to the player, GoldenEye's settings changed what a mission asked for, and Dark Souls offered no setting at all.

Enemy design is the choice of what opposes the player and how it behaves. Nishikado, Iwatani, Jarvis, Miyamoto and Bungie's Jaime Griesemer describe their choices here, from invaders that shoot back to Grunts that panic.

A falling-block game drops pieces into a well, lets the player steer and turn them, and clears filled rows or matched groups. Alexey Pajitnov's Tetris set the rules in Moscow in the mid-1980s; the Game Boy made it universal; and Welltris, Columns, Dr. Mario and Puyo Puyo each changed one part of them.

A Fatality is the secret finishing move Mortal Kombat lets the winner perform on a beaten, dazed opponent. Midway's 1992 arcade game made them its signature; Nintendo renamed and replaced four of them on the Super NES in 1993, the Mega Drive hid them behind a cheat, and the sequels added Babalities, Friendships and Animalities. The series still sells on them.

Horror games played through the character's own eyes. A ZX81 maze with a Tyrannosaurus in it showed the idea in 1982; on the PC between 1997 and 2004 Realms of the Haunting, Aliens Vs Predator, System Shock 2, Undying and Doom 3 worked out the method the period press described: sound before sight, scarce light, scares placed for the moment of false safety, and suspense over gore. Amnesia, P.T. and Resident Evil 7 carried it on.

Fog of war hides what the player's own forces cannot see. Computer wargames had it from their first years, and designers argued about it in print through the 1980s; Empire painted the unexplored world black, the real-time strategy games of the 1990s made the black map standard, and Warcraft II added a second fog that closes back over ground your units have left.

Game design is deciding what a game asks of its player and what it gives back. Designers explained their methods in the magazines of 1982 to 1997: Chris Crawford's advice to beginners and his revision of it, a 1984 designers' panel, Sid Meier on the player's role, and Miyamoto's miniature garden.

A game space crossed at will, its tasks taken in any order while the world carries on without the player. The Hobbit's wandering characters in 1982, Elite's trading in 1984 and Mercenary's three routes to escape in 1985 were described long before the name existed; DMA Design's Body Harvest and Grand Theft Auto made it a city, and the phrase itself was in the magazines by 1996.

A password packs the game's state into characters or a grid of dots that the player writes down and types back in, so a cartridge can save progress with no memory of its own. Metroid's 24 characters, Mega Man 2's 5×5 grid and the JUSTIN BAILEY code show how it worked and what it cost.

The rule that a dead character stays dead, with no saved game to bring it back. Rogue built it in by deleting the save file; the first home-computer reviews of Rogue in 1986-87 explained the rule and printed ways round it. The word itself turned up in a Your Spectrum hacking column in 1985, spread through arguments about online role-playing games around 2000, and was a familiar term in Edge by 2011.

Point-and-click adventures replaced the typed parser with a cursor: ICOM's Deja Vu on the Macintosh in 1985, Lucasfilm's on-screen verbs from Maniac Mansion (1987), Sierra's icon bar from King's Quest V (1990), and then ever fewer verbs, down to the three-part pop-up of Full Throttle and The Curse of Monkey Island.

Handheld design worked inside a fixed budget of screen, battery and pocket. Nintendo chose LCD over fancier parts for cost and battery life (Retro Gamer, 2008, on Yokoi); the 1989-90 press weighed the Game Boy's 20 hours and jacket-pocket size against the Lynx's colour screen and three hours.

How the designers of Sokoban, Tetris, Boulder Dash and Lemmings built deep games from a handful of rules, in their own words: Pajitnov's seven shapes and his line between a puzzle and a game, Liepa's rocks-and-dirt cellular automaton, DMA Design's skills added one at a time, and the reviewers who named the principle, from Computer Gaming World in 1988 to Edge in 2001.

Judging button presses against a music track. PaRappa the Rapper (1996) switched between four CD audio tracks by score; the Japanese press named the genre "rhythm action" in 1997; Konami's Bemani division built the scrolling chart and the peripherals; Harmonix's founder credits PaRappa for Guitar Hero.

Players' and speedrunners' term for reaching part of a game by a route its makers did not intend, such as finding Metroid's ice beam before the bombs. A reader used the phrase without explanation in Classic Gamer Magazine in 2004, Retro Gamer described Super Metroid players practising it in 2005, and in 2007 Edge defined it as 'the use of a route other than that intended by the game creators'.

Split-screen gives each player their own view of one display. Spy vs Spy and Pitstop II made it a two-player fixture on the Commodore 64 in 1984-85, Lotus Esprit Turbo Challenge carried it to the Amiga, and Super Mario Kart to the Super NES; the Nintendo 64's four controller ports made four-way splits the norm in Mario Kart 64 and GoldenEye 007. Reviewers named the price each time: less to see, and a slower game with four.

Stealth mechanics make the enemy something to avoid rather than to shoot. Castle Wolfenstein (1981) already had patrolling guards, a pursuing SS and a stolen uniform; Metal Gear (1987) split play into sneaking and alarm; and in 1998 Metal Gear Solid, Tenchu and Thief turned alert states, shadows and noise into systems the player could read. Hitman and Splinter Cell took disguise and light further.

Tank controls steer a character by turning it on the spot and walking it the way it faces, whatever the camera does. Alone in the Dark used the scheme in 1992 and Resident Evil made it famous; Tomb Raider and Grim Fandango used it too. Players complained from the start, Resident Evil 4 kept part of it on purpose, and the name, borrowed from the way a tank is driven, was in print by 2012.

Combat in which the player gives orders and the game resolves them before anything else happens. Computer wargames took the turn from board wargames, and role-playing games took the combat round from Dungeons & Dragons: Wizardry's review in 1982 said simply that "Encounters are fought in turns". Rebelstar's action points and opportunity fire reshaped the squad game, Dragon Warrior brought menu battles to the NES, and American magazines were using the word "turn-based" by 1991, once real-time games gave it something to be contrasted with.