The Vault · Techniques & Technology
Techniques & Technology
The clever tricks and deep system knowledge that made magic happen.
156 articles
Active Time Battle
Time flows in combat
Active Time Battle is Square's patented combat system: each character has a time gauge, acts only when it fills, and enemies keep attacking while the player decides. Edge defined it for Final Fantasy VII in 1996 and reviewed Final Fantasy Tactics, Parasite Eve and Xenogears as variations on it.
AGI Engine
Sierra's Adventure Game Interpreter
Sierra's Adventure Game Interpreter ran the 3-D Animated Adventures from King's Quest (IBM PCjr, 1984) to Manhunter: San Francisco, at 160×200 with a typed verb-noun parser, until SCI replaced it from King's Quest IV.
AGSP
Any Given Screen Position
Putting the C64's whole screen anywhere by combining VSP for the horizontal and a line crunch for the vertical - the trick behind full-screen scrolling games and demos, and identifiable by the blanked lines it leaves at the top.
Analogue Control
Degrees of freedom
Analogue control reads how far a stick is pushed, not just which way. Atari sold it on the 5200 in 1983 with a stick that would not centre; the Nintendo 64 thumb stick made Mario walk or run by degree in 1996, and Sega and Sony followed with analogue pads of their own.
Arbitrary Code Execution
Playing the game's memory
The most powerful speedrunning exploit - manipulating game memory through normal inputs to execute arbitrary code, enabling impossible shortcuts and instant wins.
Arpeggio
Chords from a single channel
Arpeggios rapidly cycled through notes of a chord, simulating polyphony on sound chips limited to single-note channels—a defining technique of chiptune music.
ASCII Art
Pictures from punctuation
ASCII art is a picture made of printable text characters. Period magazines trace it from line-printer pictures downloaded from CompuServe around 1980, through the ANSI colour art and smileys of the bulletin boards, to the ASCII logos of the 1990s Amiga scene.
Attract Mode
Arcade marketing display
Attract mode displayed automated gameplay demonstrations on idle arcade machines, enticing players to insert coins through flashy visuals, high score tables, and gameplay previews.
Attribute-Aware Design
Designing for the ZX Spectrum's two-colours-per-cell rule
How Spectrum designers and programmers worked with the platform's two-colours-per-cell rule: monochrome rooms, block alignment, colour pushed to the border, transparent printing, masking, and the attribute byte reused as the level map.
Audio Programming
Sound from code
Audio programming on vintage hardware demanded intimate knowledge of sound chips, precise timing, and clever techniques to achieve musical results.
Bank Switching
Expanding memory through hardware tricks
Bank switching allows systems with limited address space to access more memory by swapping different memory regions into the same address range.
Base Building
Construction strategy
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, called Warcraft and Command & Conquer copies of it, and by 1998 used "base-building game" as a genre label.
BASIC Curricula
Teaching code in schools
BASIC curricula in schools introduced millions of students to programming concepts through hands-on coding on classroom computers.
BASIC V2 Reference
Complete command reference
Complete command reference for Commodore 64 BASIC V2
Battery Backup
Cartridge save memory
A lithium cell in the cartridge keeps its work RAM powered while the console is off, so a game can save without a disk or a password. Family BASIC had it in 1984; The Legend of Zelda's gold cartridge made it famous in 1987; a CR2032 still does the job.
Beeper Music
Single-channel melody on the Sinclair ZX Spectrum's one-bit speaker
How the 48K Spectrum's single speaker bit produced continuous in-game tunes and three-voice harmony: Matthew Smith's interleaved game loop, Tim Follin's multi-channel routines, and what they cost the rest of the program.
Blast Processing
Marketing meets hardware
Blast Processing was Sega of America's 1992-93 marketing term for the Genesis. Sega's own magazine defined it as displaying one image while loading another; the developer manual never names it; the word came from a Mega-CD interview.
BOBs: Blitter Objects
Software sprites on the Amiga
BOBs used the Amiga's Blitter to draw sprites into the playfield—offering unlimited objects at the cost of CPU coordination and flicker-free rendering.
Branching Narrative
Your story, your choices
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.
BSP Trees
3D rendering optimisation
A BSP tree sorts a level's walls in advance so the renderer can draw them in order from any viewpoint. John Carmack learned it from Bruce Naylor's papers in April 1993 while squeezing Wolfenstein 3D onto the SNES, rebuilt Doom around it, and took it into 3D with the PVS for Quake.
Cel Shading
3D with cartoon style
Cel shading draws 3D models in flat colour bands with heavy outlines to look hand-drawn. The name came from LightWave's Cel Shader in 1997; Sega applied it to Jet Set Radio in 2000, Nintendo's cel-shaded Link stunned Spaceworld 2001, and by 2003 magazines called it a fad.
Character Graphics
Building worlds from 8×8 blocks
Character graphics used redefined text characters as game graphics, enabling colourful displays with minimal memory on systems designed primarily for text.
Character-Shift Parallax
Parallax by redrawing the font
The C64 has one background layer, so its games faked a second by rolling the pixel definitions of a few characters against the direction of the scroll. Achim traces it to Bounder, Parallax and Marauder; John Rowlands added it to Mayhem in Monsterland in an hour.
Client-Side Prediction
Making lag invisible
Client-side prediction lets a networked game act on the player's input before the server confirms it, then corrects the result when the answer arrives. Magazines in 1996-97 describe id Software introducing it in QuakeWorld, its PUSHLATENCY command, and the rubber-band corrections that came with it.
Code Wheels
Analog DRM
A code wheel is a pair of printed discs a game asks the player to consult before it runs, so the disk itself could ship unprotected. In print from Starflight in 1987 to Monkey Island's Dial-A-Pirate, with reviewers recording both the jokes and the black-on-black wheels.
Collision Detection
When objects meet
Collision detection determined when game objects touched, using techniques from simple bounding boxes to pixel-perfect checks, each trading accuracy for performance.
Colour Clash
The Spectrum's curse
The ZX Spectrum stores colour per 8×8 cell, not per pixel, so anything drawn into a cell shares its two colours with whatever is already there. The period press called it "attribute problems" and reviewed games on how they handled it.
Copy Protection
The anti-piracy arms race
Copy protection evolved from simple disk tricks to elaborate physical manuals and hardware dongles, creating an ongoing battle between publishers and crackers.
Copylock
The protection standard
Rob Northen's disk protection system that became the industry standard on Amiga and Atari ST, using sophisticated techniques to detect original disks and resist cracking.
Crafting Systems
Making from materials
A crafting system lets the player make items from gathered ingredients. In the magazines held here it runs from Secret of Evermore's alchemy in 1995 through the trade skills of Ultima Online and EverQuest to the recipes, forges and crafting stations reviewers judged in the MMORPGs of 2003-04.
Cycle Accuracy
Emulation timing tiers
Cycle-accurate emulation reproduces what the hardware does on each clock cycle. The sources here show why: games that hang when timing is approximate, chips that steal bus cycles from the CPU by documented rules, and emulator authors who set "cycle-exact" as the goal.
Data Compression
Fitting more into less
Compression techniques allowed game developers to fit larger games into limited ROM and RAM by encoding data more efficiently, from simple RLE to sophisticated algorithms.
Destructible Terrain
Worms' secret weapon
The technique of modifying bitmap landscapes in real-time, famously used in Worms to create satisfying explosions that reshape the battlefield.
Dialogue Trees
Branching conversation
A dialogue tree offers the player a short list of replies, each opening another. The magazines here trace it from Law of the West's four replies in 1985 through Sierra's "conversation tree" of 1992 to the statistic-gated dialogue of Fallout and Planescape: Torment.
Difficulty Design
Balancing challenge and accessibility
Difficulty design is the choice of how hard a game is and who can change it. The sources here run from the arcade trade's "easy to learn, hard to play" rule and the Atari VCS difficulty switches to GoldenEye's objective-changing modes and The Lost Levels.
Digitised Sprites
Real actors, pixel form
Digitised sprites are video frames of real actors reduced to a machine's palette. In use on the C64 by 1988, made famous by Pit-Fighter and Mortal Kombat; not to be confused with Rare's rendered sprites.
Dirty Rectangles
Efficient screen updates
Dirty rectangle rendering optimised screen updates by tracking and redrawing only the areas that changed, saving CPU cycles when most of the display remained static.
Disk Fastloaders
Cutting load times on the Commodore 1541
The 1541 is slow because its bus protocol is bit-banged in software around the VIC-II's DMA; fastloaders replace both ends of it. Epyx claimed five times, Datel's Warp 25 two hundred blocks in six seconds, and JiffyDOS printed the stopwatch figures.
Disk Protection
Copy prevention on floppy
Disk protection techniques prevented casual copying of floppy disks through intentional errors, non-standard formatting, and hardware tricks.
Dithering
More colours from fewer
Dithering created the illusion of additional colours by interleaving pixels of different shades, expanding limited palettes through optical mixing.
Double Buffering
Smooth, tear-free graphics
Double buffering drew to an off-screen buffer while displaying another, eliminating visual tearing and enabling smooth animation even on slow hardware.
DYCP
Different Y Character Position
The C64 scroller where each letter bobs up and down on its own sine as it crosses the screen. Explained in print by Pasi 'Albert' Ojala in 1991, whose article is why the technique is documented at all.
Emulation Techniques
Software becoming hardware
An emulator makes one machine's software run on another by imitating its hardware. The magazines here give the method in Chris Hardy's words, the interpreter-versus-recompiler choice in Simon Goodwin's, MAME's growth from 1997, and the UltraHLE and Connectix cases of 1999.
Enemy Design
Making meaningful opposition
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.
Falling Block
Puzzle game foundation
A falling-block game drops pieces into a well and clears filled rows or matched groups. Tetris defined it, and the 1988-94 reviews here describe the rules, the Game Boy pack-in, and how Columns, Dr. Mario and Puyo Puyo varied them.
Fast Loaders
Beating the bottleneck
Fast loaders accelerated tape and disk loading on 8-bit computers, reducing frustrating wait times through optimised data transfer routines.
Fatalities
Finish them
A Fatality is the finishing move Mortal Kombat lets the winner perform on a beaten opponent. The moves sold the game, were renamed and replaced on the Super NES in 1993, were named in the US Senate hearings that winter, and multiplied into Babalities, Friendships and Animalities in the sequels.
Filmation Engine
Isometric illusion
Ultimate Play the Game's Filmation engine gave 8-bit isometric games solid, masked, flicker-free objects — and set the template that a hundred Spectrum arcade adventures followed.
Filter Sweeps
Moving through the frequency spectrum
Filter sweeps create dynamic timbral changes by gradually adjusting filter cutoff frequency, a signature effect of the C64's SID chip.
First-Person Horror
Through terrified eyes
First-person horror frightens a player who sees through the character's eyes. The 1997-2004 PC reviews here describe the method: sound before sight, scarce light, set-pieces at the moment of false safety, and suspense over gore.
Fixed-Point Maths
Smooth movement without floating point
Fixed-point arithmetic gives 8-bit systems sub-pixel precision for smooth movement, physics, and animation—all with fast integer operations.
FLD
Flexible Line Distance
A C64 trick that inserts gaps between character lines, pushing the graphics below them down the screen. Unusually for a scene effect, it appeared in commercial games before it appeared in demos.
FLI
Flexible Line Interpretation
A C64 trick that re-triggers the VIC-II's colour fetch on every pixel line instead of every eighth, multiplying the colours available in a bitmap — at the cost of a permanent grey scar down the left of the screen.
FM Synthesis
Frequency modulation music
FM synthesis makes complex timbres by letting one oscillator vary another's frequency. Chowning's method became Yamaha's chip family: the YM2151 in arcades, the YM3812 on the Ad Lib and Sound Blaster, the YM2413 in MSX-MUSIC, the YM2612 in the Mega Drive.
Fog of War
Strategic information hiding
Fog of war hides what the player has not scouted. Computer wargames argued about it from 1982, Empire painted the unexplored world black, and Warcraft II split the black shroud from the fog that returns when your units leave.
Force Feedback
Feel the game
Force feedback puts motors in a controller so the game can push back. Hard Drivin' had a motorised steering column in 1989, Immersion's Louis Rosenberg pitched the modelled version in 1996, and by 1998 Microsoft and Logitech were shipping wheels and sticks the games had yet to catch up with.
FPP
Flexible Pixel Position
The most permissive of the C64 vertical tweaks: every single pixel line of graphics placed anywhere on screen, independently of every other — so graphics can be reversed, repeated or stretched at will.
Frame Animation
Sprite-based motion
Frame animation creates movement by displaying sequences of pre-drawn sprite images, with quality determined by frame count, timing, and artistic principles borrowed from traditional animation.
Frameskipping and Interpolation
Running the logic slower than the screen
When a C64 game runs out of raster time, it can render less often than it thinks (frameskipping) or think less often than it renders, filling the gaps with linear interpolation. Cadaver set out both in his Rant 9 and shipped the second in Metal Warrior 4.
Freescape
Solid 3D on a machine with no maths
Incentive's engine gave 8-bit micros a real three-dimensional world — filled polygons, free movement, looking up and down — four years before consumer 3D hardware existed. CRASH gave the first game built on it 97%.
Full Motion Video
Live action in games
Full motion video played filmed actors from CD. Sega called Night Trap the first interactive movie in 1992, The 7th Guest shipped 36 minutes of it, Wing Commander III put Mark Hamill on four CDs, and by 1998 Computer Gaming World was writing its obituary.
Game Design
The craft of creating play
Game design is deciding what a game asks of its player and what it gives back. The 1982-97 sources here are designers on their own method: 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.
Ghost AI
Pac-Man's four personalities
Pac-Man's four ghosts each hunt by a different rule so the pack comes from all directions. Toru Iwatani's own account of why, the chase-and-disperse waves, the power-pellet reversal, and the pattern play the rules made possible.
Hard restart
Working around the SID's ADSR bug
Every C64 music driver silences and resets a SID voice two frames before each note, because the chip's envelope generator can otherwise stall for 1.7 frames. The workaround is older than the explanation.
Hardware Scrolling
Smooth movement without moving data
Hardware scroll registers let the display shift smoothly pixel-by-pixel without copying memory—essential for fast, smooth side-scrolling games.
Havok
Physics middleware
Havok was the Dublin physics middleware that released beta code in 1999, merged with Ipion in 2001, aimed version 2.0 at ragdoll characters in 2003, and by 2005 was, in Edge's words, the standard by which the others were judged, with Half-Life 2 and Halo 2 to show for it.
Hitboxes
Collision boundaries
Hitboxes define the invisible collision boundaries around game objects, determining when attacks connect, pickups are collected, and characters collide with the world.
How a Cassette Becomes a Game
From magnetic stripes to moving sprites
Cassettes were slow, cheap, and everywhere. Here's how data marched from tape to RAM, one bit at a time.
Interrupt-Driven Music
Sound without blocking
Interrupt-driven music used timer interrupts to update sound chips at regular intervals, allowing music playback while the CPU handled game logic.
Isometric Projection
3D from 2D
Isometric projection created the illusion of three-dimensional space on 2D screens, enabling exploration games impossible with flat side-views.
KERNAL I/O Routines
The Commodore 64’s built-in service desk
The C64’s KERNAL ROM exposes a patchable API for keyboard, screen, tape, disk, and serial I/O—perfect for BASIC and assembly alike.
Lenslok
The hated prism
The physical copy protection device that required players to decode on-screen codes through a plastic prism - launched on Elite in late 1985 and disliked from the first month.
Linecrunch
Squeezing eight pixel rows into one
A C64 trick that crushes character lines down to a single pixel row, pulling the screen upward. Unlike FLD it can move bitmap graphics — and it first appeared not in a demo but in a cracktro.
Link Cable
Wired multiplayer
The Game Boy's link cable came in the 1989 box as the Video Link Cable, joined two machines for two-player Tetris, grew a Four Player Adapter in 1991, and became the point of Pokémon's two editions in 1998.
Lookup Tables
Trading memory for speed
Lookup tables pre-calculated expensive operations like trigonometry and multiplication, storing results for instant retrieval on processors too slow for real-time maths.
Manual Protection
Look it up to play
Manual protection required players to consult physical documentation to play games, deterring piracy through information unavailable on copied disks.
Memory Management
Making the most of limited RAM
Memory management techniques enabled complex games on hardware with kilobytes of RAM, from bank switching to compression to careful data structure design.
Memory Mapping
Addresses for everything
Memory-mapped I/O places hardware registers at specific addresses, allowing software to control graphics, sound, and input by reading and writing memory locations.
MOD Format
The tracker music revolution
The MOD format combined samples with pattern-based sequencing in a single self-contained file, becoming the standard for game and demo music on the Amiga and across the chiptune scene.
Mode 7
SNES rotation and scaling
Background mode 7 of the Super NES PPU rotates, enlarges and reduces a single 1024×1024-dot layer through a 2×2 matrix in registers $211B–$211E; changed every scanline by HDMA it becomes the perspective floor of F-Zero and Pilotwings.
Model 2
Arcade 3D revolution
Model 2 was Sega's Model 1 polygon engine with texture-mapping hardware from General Electric's flight-simulator division, co-developed from August 1992. It debuted with Daytona USA in 1994 at 300,000 textured polygons a second and was succeeded by the unrelated Model 3.
Motion Capture
Recording reality
Motion capture records a performer's movement as data for a 3D character; Sega AM2 used a magnetic system on Virtua Fighter by 1994, Acclaim, Gremlin and Psygnosis built optical studios in 1995, and by 1998 it was standard practice and already being argued against.
Multidirectional Scrolling
Eight ways, or any way
The C64 shifts 1,000 bytes of screen memory by hand every time the hardware scroll register wraps, so multidirectional scrolling is a scheduling problem: spread the shift over frames, hide it behind a second screen, and decide whether the scroll is locked to eight directions or free.
Object Pooling
Reuse, don't reallocate
Object pooling pre-allocates and reuses game objects instead of creating and destroying them, avoiding memory fragmentation and allocation overhead.
Open World Design
Freedom to explore
A game space crossed at will, its tasks taken in any order while the world carries on. Described for Elite in 1984, weighed against Elite for Mercenary in 1986, and sold as a city that "breathes" for Grand Theft Auto in 1997; the phrase itself appears in 2000.
Opening the borders
Drawing outside the frame the VIC-II reserves
Tricking the C64's VIC-II into never starting its border, so sprites and graphics can occupy the frame around the screen. The first C64 trick to become a competitive sport, and the one whose priority is most disputed.
Palette Cycling
Animation without redraw
Palette cycling created animation effects by rotating colour values rather than redrawing graphics, enabling flowing water, glowing effects, and pulsing lights without CPU overhead.
Parallax Scrolling
Depth through motion
Parallax scrolling moved background layers at different speeds to create an illusion of depth, transforming flat 2D games into seemingly three-dimensional spaces.
Password Systems
Save without battery
A password packs the game's state — level, weapons, tanks — into characters or a dot grid the player writes down and types back in, so a cartridge can save without a battery. Metroid's 24 characters, Mega Man II's 5×5 grid, and the JUSTIN BAILEY code that fell out of one.
Permadeath
Death means death
The rule that a dead character's save is deleted. The 1986-87 reviews of Epyx's Rogue explained the rule and printed the disk-copy workaround; Antic's type-in A-Rogue kept it; Edge named it "permadeath" in 2013.
PETSCII Character Chart
Every character code the C64 knows about
PETSCII codes, screen codes, and control characters—the complete reference for displaying text and graphics on the Commodore 64.
Physics Engines
Simulating the real world
Physics engines became a separable component of games between Trespasser's muscle-driven dinosaurs in 1997 and the physics-card pitch of 2005, with MathEngine and Havok licensing the first realtime engines at the end of the 1990s and racing games as the first customers.
Pixel Art
Painting with squares
Drawing by hand in the dots of a low-resolution, fixed-palette display. Antic used the phrase in 1984 for Lucasfilm's Gary Winnick; Amiga Action put "pixel artists" in quotes in 1989; Bullfrog, Domark and Psygnosis artists explained the 16-colour craft in 1992; by 1994 it was a job title.
Point and Click
Mouse-driven adventure
Point-and-click adventures replaced the typed parser with a cursor: ICOM's Deja Vu on the Mac in 1985, Lucasfilm's on-screen verb menu from Maniac Mansion, and Sierra's icon bar from King's Quest V.
Portable Game Design
Constraints breed creativity
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.
Position-Independent Code
Code that runs anywhere
Code that runs correctly wherever it is loaded, because every reference is relative to the program counter. The 6809's architects made it their highest-priority design goal (BYTE, 1979), Motorola's manual made it a rule, OS-9 made it a requirement; 6502 programmers managed it by effort.
Pre-Rendered Backgrounds
Static beauty
A pre-rendered background is a picture of a place with polygon characters drawn over it from a fixed camera. Reviewers traced the formula from Alone in the Dark through Myst to Resident Evil, and Final Fantasy VII made it the look of the PlayStation's biggest game.
PRINT vs POKE
Why games don't use PRINT statements
Performance comparison of PRINT and POKE for screen output—and why understanding the difference makes you a better C64 programmer.
Procedural Generation
Algorithmic content creation
Procedural generation created game content through algorithms rather than manual design, enabling vast worlds, endless replayability, and experiences that fit in kilobytes.
Pseudo-3D Road
OutRun's famous perspective
A perspective road drawn as horizontal strips bent for corners and shifted for hills, with sprites scaled by distance. Sega's Turbo had it in 1982, Out Run perfected it in 1986, and conversion programmers wrote the road routine first.
Pulse Width Modulation
Shaping square waves
Pulse width modulation varied the duty cycle of square waves, transforming simple bleeps into rich, evolving tones that defined the sound of chip music.
Puzzle Game Design
Elegant rules, emergent depth
How puzzle games are made: few elements, abstract presentation, felt progress. Stated by Computer Gaming World in 1988 ("simple in concept and play, but also addictively challenging"), by Edge in 2001 ("Accessibility alone determines whether a puzzle game lives or dies"), and at length by Alexey Pajitnov in 2007.
Ragdoll Physics
Dynamic death
Ragdoll physics hands a jointed character to the physics engine so it falls as the forces dictate; described by Chris Hecker in Edge in 1998, shipped in Unreal Tournament 2003 via MathEngine's Karma, and dismissed by Gabe Newell as flopping-around corpses once Half-Life 2 had made physics a tool instead.
Random Numbers
RND() internals and techniques
RND() internals, techniques, and patterns for game development
Raster Effects
Per-scanline graphics tricks
Raster effects change graphics parameters during screen drawing, creating colour bars, split screens, and effects beyond normal hardware limits.
Raster Interrupts
Precision timing with the video beam
Raster interrupts trigger code at exact screen positions, enabling split-screen effects, colour bars, and multiplexed sprites that defined 8-bit graphics.
Raster Tricks
Exploiting the electron beam
Raster tricks push hardware beyond specifications by precisely timed manipulation during screen display, achieving impossible-seeming effects.
RenderWare
Cross-platform 3D middleware
RenderWare began in 1994 as Criterion Software's software-only 3D library for 386 and 486 PCs, was rewritten from scratch as RenderWare3 for the PlayStation 2 generation, powered Grand Theft Auto III after DMA Design lost most of its staff, and went to Electronic Arts with Criterion in 2004.
Rhythm Matching
Play to the beat
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.
Ring Buffer
Circular data, fixed memory
A fixed block of memory used as a queue, with read and write indexes that wrap. BYTE explained it to hobbyists in 1977; Tim Follin's Agent X II engine uses a 16-entry one, wrapped with AND 15, for its echo; Amiga Exec's interrupt handlers fed device tasks through them.
Rotoscoping
Animation from life
Rotoscoping traced real human movement frame by frame, creating fluid animation in games like Prince of Persia and Another World that felt remarkably lifelike.
Rumble Pak
Feel the game
Nintendo's Rumble Pak plugged into the N64 controller and shook it on cue. Announced as the Jolt Pak and shipped with Star Fox 64 in spring 1997, it was retrofitted to Mario 64 and Wave Race in Japan, sold for £15 in Britain, and answered by Sony's DualShock in 1998.
Run-Length Encoding
Simple compression
Run-length encoding compressed data by storing repeated values as count-value pairs, dramatically reducing storage for graphics with large uniform areas.
SCI Engine
Sierra's Creative Interpreter
Sierra's Creative Interpreter replaced AGI from King's Quest IV (1988): an object-oriented scripting language on a virtual machine, 320×200 graphics, MT-32 and AdLib music, and from 1990 an icon interface in place of the parser.
Screen Memory
How the C64 displays text and graphics
Screen RAM, colour RAM, and the VIC-II—understanding how 1000 bytes create 40×25 characters of colourful text.
Scrolling
Moving through game worlds
Scrolling techniques expanded game worlds beyond single screens, from smooth hardware-assisted movement to creative software solutions that defined platformers and shooters.
SCUMM
Script Creation Utility for Maniac Mansion
SCUMM powered LucasArts adventure games from Maniac Mansion through The Curse of Monkey Island, providing tools that let designers focus on puzzles and dialogue rather than low-level code.
Self-Modifying Code
Code that rewrites itself
Self-modifying code changed its own instructions at runtime, enabling impossible optimisations on 8-bit systems by treating code as data.
Sequence Breaking
Playing out of order
A speedrunner's term for taking a route the game's makers did not intend: the ice beam before the bombs in Metroid. Edge defined it in 2007 as "the use of a route other than that intended by the game creators"; Retro Gamer used it unexplained the same year. No earlier use is held.
Size Coding
The art of compression
Size coding emerged from demo scene competitions with strict byte limits, pushing programmers to achieve impossible effects in 64KB, 4KB, or even 256 bytes.
Software Scrolling
When hardware won't help
The ZX Spectrum has no scroll hardware, so scrolling means moving screen bytes: character steps, one-pixel rotates, or the stack-pointer "push-scroll" Software Creations used for Ghosts 'n' Goblins. The choice shaped how Spectrum games moved.
Sound Drivers
Audio engine software
Sound drivers were the software engines that controlled audio hardware, translating composer's music data into the bleeps, samples, and synthesised sounds that defined each platform's acoustic character.
Speedcode
Loop unrolling, taken to its conclusion
Replacing a loop with thousands of straight-line instructions to strip out the cost of looping. On the C64 it was the technique that broke raster-split and DYCP records — and it is usually generated, not written.
Split-Screen
Sharing the view
Split-screen gives each player their own view of one display. Reviewers traced it from Spy vs Spy and Pitstop II on the C64 through Lotus on the Amiga and Super Mario Kart to the four-way splits of Mario Kart 64 and GoldenEye, naming the cost each time: less to see, and slower with four.
Sprite Animation
Bringing pixels to life
Frame-by-frame sprite animation creates the illusion of movement by cycling through carefully designed images at controlled intervals.
Sprite crunching
Shrinking a sprite by abusing a VIC-II glitch
A cycle-exact C64 trick that corrupts the VIC-II's internal sprite counter to make sprites shorter than the hardware allows — documented byte by byte by Crossbow of Crest, who got them down to 17 lines and left the record open.
Sprite Flicker
Exceeding hardware limits
Sprite flicker rapidly alternated which sprites displayed each frame, allowing games to show more objects than hardware supported at the cost of visible flickering.
Sprite Multiplexing
More sprites than hardware allows
By repositioning hardware sprites mid-frame as the raster beam passes, programmers displayed far more objects than the hardware officially supported.
Sprite Scaling
Pseudo-3D depth
Sprite scaling created the illusion of 3D depth by drawing sprites at different sizes based on distance, enabling racing games, shooters, and flight simulators on 2D hardware.
Sprite stretching
Telling the VIC-II to read the same line twice
Holding the C64's sprite graphics pointer still for a raster line so the same row of sprite data is drawn again, stretching a sprite to any height. The forgiving half of a pair whose other half needs cycle-exact timing.
Sprites
Hardware-accelerated game objects
Sprites are hardware-supported graphical objects that move independently of the background, fundamental to 2D game graphics across platforms.
Stable Raster
Cycle-exact timing
The double-IRQ technique that achieves cycle-exact synchronisation with the VIC-II raster beam, enabling perfect mid-screen effects on the Commodore 64.
State Machines
Organising game logic cleanly
State machines bring order to complex game logic—managing title screens, gameplay, pauses, and game-overs through clear transitions and isolated behaviour.
Stealth Mechanics
Unseen and unheard
Stealth mechanics make the enemy something to avoid. The 1981-2002 sources here follow the idea from Castle Wolfenstein's patrols and Nazi uniform, through Metal Gear Solid's alert states, to Thief's light gem and the disguises of Hitman.
Super FX Chip
Cartridge silicon
Argonaut's Graphic Support Unit for Super NES cartridges: a 10.74 MHz RISC-style processor sharing the game pak's ROM and RAM, plotting pixels into PPU character format so that Star Fox (1993) could draw polygons. The Super FX 2 ran at 21.477 MHz.
Tank Controls
Character-relative movement
Tank controls steer a character by turning on the spot and walking the way it faces, whatever the camera does. The 1993-2012 sources here cover the fixed cameras of Alone in the Dark, the slow retreats of Resident Evil, the side-step Resident Evil 4 refused, and the late arrival of the name.
Tech-tech
Making a logo wave a line at a time
The C64 effect where a logo ripples horizontally, each raster line offset along a sine. Documented by Pasi 'Albert' Ojala, and later rebuilt on FLI by Compyx/Focus after a 25-year gap.
Texture Mapping
Images on polygons
Texture mapping wraps a flat picture onto a polygon. Named on the PC for Strike Commander in 1991, it defined Doom and Ridge Racer, gave the PlayStation its warping textures, and came built into the Nintendo 64 with mip-mapping.
The Game Loop
The heartbeat of every game
Every game runs on the same fundamental pattern: read input, update state, render graphics, repeat. Understanding the game loop is the first step to building anything interactive.
Tile Maps
Building worlds from blocks
Tile maps constructed game worlds from small reusable graphic blocks, enabling large levels within tight memory constraints while simplifying collision detection and level design.
Tile-Based Collision
Efficient collision detection for platformers
By checking which tiles a character overlaps rather than testing every object, tile collision provides fast, memory-efficient collision detection for platform games.
Tile-Based Graphics
Building worlds from small pieces
Tile-based graphics build screens from small reusable images, enabling memory-efficient game worlds on limited hardware.
Trainers
+5 and counting
A trainer is a set of cheats patched into a game — infinite lives, energy, time — offered from a menu before it starts. Crackers added them to releases (Retro Gamer, 2005; a Medway Boys cracker's recollection of 1986-90); Datel sold a "TRAINER MODE" on the Action Replay (1992); Silkworm's own cheat used the word (1989).
Turn-Based Combat
Strategic pacing
Combat resolved in rounds after the player commits every character's action. Described for Wizardry in 1982 ("Encounters are fought in turns"), sold with Dragon Warrior in 1989, and named "turn-based" by the British press in 1994-95 to say what Secret of Mana and Super Mario RPG were not.
Twister
Rotating a shape by rebuilding it from pre-drawn line fragments
The rotating-column effect and its relatives - x-rotators, waving carpets - built on the C64 by running FLI on every second line, which buys back 63 cycles to spend on the effect itself.
Unit Pathfinding
Navigation intelligence
How a game moves a unit from A to B on its own. Wargames were finding the cheapest route across terrain by 1983, Paradroid ran its robots on hand-keyed patrol routes, and by the late 1990s the 'pathfinding problem' was the standing complaint against real-time strategy.
User Defined Graphics (UDGs)
Custom 8×8 character glyphs on the Sinclair ZX Spectrum
Twenty-one programmer-supplied 8×8 patterns, codes 144 to 164, that the Spectrum's print routine treats as ordinary letters: the manual's route from BASIC into pixel graphics.
Variables and Memory
BASIC memory management
How variables work internally and memory management for BASIC programs
Vector Graphics
Lines of light
A vector monitor draws lines by steering the beam, not by scanning pixels. Cinematronics' Space Wars brought it to arcades in 1978, Atari's Quadrascan games made it famous, Sega's Space Fury added colour, and the Vectrex took it home.
VSP
Variable Screen Positioning, or HSP, or DMA delay, or Wanker
A C64 trick that shifts the whole screen horizontally by deliberately delaying the VIC-II's DMA. It has at least four names, none of them agreed, and it can crash real hardware.
VSync
Synchronising with the display
VSync synchronised game updates with the monitor's vertical refresh, preventing screen tearing and providing consistent timing for game logic.
Y-Depth Sorting
Sprite ordering by position
The technique of sorting sprites by their Y position to create correct depth ordering in top-down and isometric games, essential for beat 'em ups and action RPGs.
Z-Machine
The portable text adventure engine
The virtual computer Infocom's text adventures ran on: a game compiled once, an interpreter per machine. Lebling described it in BYTE in 1980 with four interpreters; Infocom advertised twenty formats by 1984.
Z80 Instruction Set Reference
Selected CPU instruction reference
Reference for the most common Z80 assembly instructions with T-states, bytes, and flag effects, as Zilog's Z80 CPU User Manual gives them.
ZX Spectrum hardware ports
Talking to the ULA, the AY chip, and the joystick — one port at a time
The Spectrum's I/O port map: port $FE for keyboard, border, beeper, and tape on every model; port $1F for the Kempston joystick; ports $7FFD and $1FFD for 128K and +2A/+3 memory paging; ports $FFFD and $BFFD for the AY-3-8912 sound chip on the 128K models; the +3's disk and printer ports. Bit assignments as the Sinclair and Amstrad manuals and Chris Smith's ULA book give them.
ZX Spectrum ROM disassembly
The 16 KB ROM that boots the machine, runs BASIC, and quietly underpins every Spectrum game
Reference for the ZX Spectrum's 16 KB ROM at $0000-$3FFF — the restart vectors, the interrupt routine, the character set, the system variables, and the ROM routines a game is most likely to call, each checked against Logan and O'Hara's 1983 disassembly.