Pac-Man

Ghosts switch between three readable modes: chase, scatter and frightened. Scatter sends each ghost to a corner, frightened makes them flee while Pac-Man holds a power pellet, and they return to chase when the pellet runs out. Each mode gives the player a different situation to react to.

This is now called a finite state machine. Stealth games use the same template: Batman: Arkham Asylum guards move between idle, suspicious, engaging and hunting, and most stealth guards cycle idle, combat, search and back to patrol when a timer expires.

Color Switch turned Pac-Man's minor color-change moment into its whole game. David Reichelt noticed that Pac-Man's ghosts change color after a power pellet only as a side element, and made color switching Color Switch's core mechanic. He blended it with Simon, Uno, the Gmail loading ball and one-tap play from Flight.

He sketched the concept in 20 minutes and had a demo 10 minutes later. "Inspiration from one idea is cloning."

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Color Switch bet on Pac-Man-style fan loyalty when relaunching. After his game was pulled from the App Store, Reichelt relaunched it on his own account, citing Pac-Man reappearing after 20 years as proof fans return. It climbed the charts with no marketing.

He held off on user acquisition for the first weeks, and the game kept doing well on organic demand.

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Each ghost chases its own target tile, so the group is learnable but unpredictable. At every intersection each ghost takes the shortest route to its own target. Blinky targets Pac-Man, Pinky aims four tiles ahead of him, Inky uses a point built from Blinky's position, and Clyde chases until he is within eight tiles, then retreats to the bottom left corner.

Inky's target comes from a line drawn from Blinky to a spot two tiles ahead of Pac-Man, extended by the same length again. Blinky is the most aggressive and predictable; the others are harder to read but can be learned, so every game plays out differently. Mark Brown calls them "hard to read and predict, but not impossibly random".

Independent simple rules created an illusion of ghost teamwork. Because Blinky comes from behind while Pinky aims ahead, the red and pink ghosts seem to spring a pincer, and Inky and Clyde seem to work the edges, with no shared information between them.

Many modern games still need a blackboard system or a squad controller to get the same effect. "Pac-Man achieved an effective illusion of cooperation decades earlier, with really simple rules."

Ghosts switch between three readable modes: chase, scatter and frightened. Scatter sends each ghost to a corner, frightened makes them flee while Pac-Man holds a power pellet, and they return to chase when the pellet runs out. Each mode gives the player a different situation to react to.

This is now called a finite state machine. Stealth games use the same template: Batman: Arkham Asylum guards move between idle, suspicious, engaging and hunting, and most stealth guards cycle idle, combat, search and back to patrol when a timer expires.

The power pellet turns the hunted into the hunter. Eating a power pellet lets Pac-Man eat the ghosts that were chasing him; an eaten ghost returns to the central pen and scores points. It was one of the earliest power-ups, maybe the first.

Descendants include Donkey Kong's hammer, Super Mario Bros.' mushroom and fire flower, Sonic's monitors and Doom 2016's Berserk sphere. Brown compares the payoff to finally downing Mr. X in Resident Evil 2.

Only four pellets per maze make each one a real decision. With just four power pellets on each map, players must choose when to eat them to get the most points and safety.

The scarcity, together with scatter waves, creates a back-and-forth rhythm of power and powerlessness. "They must be munched judiciously."

Ghosts attack in waves and retreat, giving players moments of relief. Iwatani felt constant pursuit would be too stressful, so ghosts periodically scatter to the four corners, then regroup and chase again.

"I felt it would be too stressful for a human being like Pac Man to be continually surrounded and hunted down." Left 4 Dead's AI director later used the same alternation of zombie assaults and lulls.

Difficulty rises within each level and again across levels. Scatter periods run 7 seconds twice, then 5 seconds twice, then the ghosts only chase. Blinky speeds up as dots are eaten and stops scattering when 20 dots remain.

Across levels, frightened time gets shorter, Pac-Man moves faster and is harder to control, and ghosts leave the pen sooner. The mix of chase and scatter, power and powerlessness keeps the pace from feeling repetitive.

Forgiving cornering keeps controls feeling fair. Pac-Man can still turn a corner if the stick moves when he is a few pixels past the intersection.

It works like coyote time in platformers, where the hero can still jump just after running off a ledge.

Iwatani designed around how the player feels, not what pleased him. His softer ghost waves and forgiving turns come from his view that a fun game comes from understanding how the player's mind works.

"Creating a fun game is not about satisfying yourself as a developer. It's all about the people that actually play the game."

The goal was obvious to anyone watching over a shoulder. Iwatani's rule was that the player should immediately get the point: eat the dots, avoid the monsters. No words or cultural references were needed.

He compares it to golf, where the ball goes in the hole. Obvious rules gave new players confidence to start, then the AI and difficulty curve hooked them.

A cute, non-violent eating theme drew a new audience into arcades. Iwatani saw dingy arcades full of war and shooting games that mostly drew boys and men, so he built Pac-Man around eating, with bright colours and friendly ghosts. How to Win at Video Games puts its audience at 60% female.

The idea started with eating, not shooting: the name blends the Japanese word for mouth, a pizza with a slice missing, and Pakku Pakku, the sound of eating. Midway's Ms. Pac-Man followed, adding new gameplay and better AI, possibly without Namco's approval.

Pac-Man gave players a character with a name, face and personality. Earlier games offered spaceships, cars, paddles and nameless humans. Pac-Man became games' first mascot.

Iwatani drew on cartoons: Tom and Jerry for the chases, Popeye's spinach for the power pellet, and Casper and Little Ghost Q-Taro for the ghosts.

Between-level cutscenes rested players' hands and added story. Iwatani called them coffee breaks: a calm moment after a tense level that also added character. They were among the first non-interactive scenes placed inside gameplay.

Colleagues grumbled that they wasted time and resources, but Iwatani insisted on them.

Puck-Man flopped in Japan, then became a giant hit through Midway. It launched on May 22nd, 1980 in a Shibuya movie theatre, where players preferred Namco's shooter Galaxian. In America it sold over 100,000 cabinets in its first year and took a billion dollars in quarters.

Midway picked up both games after licensing Space Invaders and renamed it Pac-Man to stop people vandalising the machine. A Billboard chart song, merchandise and a TV show followed, though Atari's 2600 port was poor.

Copies took the surface; Pac-Man's deeper ideas spread through game design. Maze clones such as Ali Baba and 40 Thieves, Lady Bug, Lock 'N' Chase and Nibbler had a brief surge but formed no lasting genre. Its structure spread instead: The Tower of Druaga influenced Zelda, John Romero cites Pac-Man for Wolfenstein 3D and Doom's level design, and Kojima sees it in Metal Gear.

Midway and Atari won a suit over K.C. Munchkin! on the Magnavox Odyssey, one of the first copyright cases in games. Pac-Land predates Super Mario Bros., and Iwatani later oversaw Pac-Man Championship Edition.

Color Switch turned Pac-Man's minor color-change moment into its whole game. David Reichelt noticed that Pac-Man's ghosts change color after a power pellet only as a side element, and made color switching Color Switch's core mechanic. He blended it with Simon, Uno, the Gmail loading ball and one-tap play from Flight.

He sketched the concept in 20 minutes and had a demo 10 minutes later. "Inspiration from one idea is cloning."

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Giving each ghost a personality makes the AI seem smarter. Each coloured ghost has its own quirks, and developers have found that distinct personalities make AI characters read as more intelligent to players.

Civilization's single-player leaders use the same idea.

Ghosts attack in waves and retreat, giving players moments of relief. Iwatani felt constant pursuit would be too stressful, so ghosts periodically scatter to the four corners, then regroup and chase again.

"I felt it would be too stressful for a human being like Pac Man to be continually surrounded and hunted down." Left 4 Dead's AI director later used the same alternation of zombie assaults and lulls.