Glossary

Completing an arcade game from start to finish using only a single credit — the original condition for which arcade games were balanced and the measure of mastery in Japanese arcade culture. 1-CC challenges are significantly harder than continue-assisted clears because arcade games were deliberately designed to consume quarters; a 1-CC requires knowing every enemy pattern, managing health deliberately, and not wasting a life on avoidable damage. In Japan, 1-CC achievement is documented in arcade rankings and gaming magazines and carries substantial prestige.

A term used in the 1980s and 1990s to describe a home console or computer port of an arcade game that replicated the original with no visible compromises in graphics, sound, or gameplay. True arcade-perfect ports were extremely rare before the PlayStation and Saturn era due to the hardware gap between arcade boards (which often used proprietary, expensive components) and consumer hardware. The phrase was frequently misused in marketing to describe ports with significant downgrades.

Also known as a "brawler," the beat-em-up is a genre in which one or two players advance through linear stages by defeating waves of enemies using melee combat. The genre reached its commercial peak in the early 1990s arcade and 16-bit era with titles like Streets of Rage and Final Fight. A defining characteristic is the ability to pick up and throw objects and enemies, combined with a limited move set that becomes more expressive through timing and combination.

A marketing term coined by Sega of America in 1993 to advertise the Sega Genesis's CPU speed advantage over the Super Nintendo. The Genesis's Motorola 68000 ran at 7.67 MHz versus the SNES's 3.58 MHz, a real but contextually limited difference; the SNES compensated with superior graphics hardware including Mode 7 and larger colour palettes. "Blast Processing" became one of gaming's most enduring examples of technically-grounded-but-misleading marketing, and is now used ironically to describe any vague hardware claim.

An input sequence — typically entered on a title screen, pause menu, or controller — that unlocks hidden functionality in a game: extra lives, invincibility, level select, or debug tools. Cheat codes originated as developer shortcuts for testing and were frequently left active in retail releases. Their golden era was the late 1980s to mid-2000s, before persistent online connectivity made server-side validation practical. Gaming magazines and schoolyard oral tradition were the primary distribution mechanisms.

Music created using the sound synthesis hardware of vintage game consoles or computers — typically the NES APU, the Commodore 64's SID chip, the Game Boy's DMG sound chip, or the Sega Genesis's YM2612. In its original context, chiptune simply described game music composed within hardware constraints. As an active musical genre, chiptune encompasses contemporary artists who compose original music on vintage hardware or software emulations, treating the aesthetic limitations of old sound chips as compositional tools.

A short animated introduction screen prepended to a pirated game by the cracking group responsible for removing its copy protection. Cracktros served as calling cards for groups competing for prestige within the demo scene's adjacent piracy subculture, displaying the group's name with as much graphical and musical flair as possible. Many cracktro coders went on to join legitimate demo groups; the aesthetic vocabulary of the cracktro — scrolling text, plasma effects, tracker music — directly influenced the broader demo scene.

A software post-processing effect applied to retro game emulation to simulate the visual characteristics of a CRT television: scan lines, phosphor glow, slight geometry curvature, and colour bleed between adjacent pixels. CRT filters range from simple scan-line overlays to sophisticated GPU shaders (such as CRT-Royale and CRT-Geom) that model the physics of aperture grille and shadow mask CRT panels. Many pixel-art games were designed with CRT display in mind, and their low-resolution sprites rely on colour bleed to produce smooth gradients.

A subculture of programmers, artists, and musicians who create "demos" — non-interactive audio-visual programs designed to showcase technical skill on constrained hardware. The demo scene originated in the Amiga and Commodore 64 communities of the mid-1980s and produced some of the most technically impressive programming of the era, achieving real-time 3D rendering, audio synthesis, and visual effects that commercial games could not match. Demo parties such as The Party (Denmark) and Assembly (Finland) remain active annual events.

A hidden message, feature, image, or joke embedded in a game (or other software) by its developers, discoverable only through non-obvious actions the game does not document. The term originates from the first recognised video game Easter egg: Warren Robinett's hidden room in Adventure (Atari 2600, 1980), where his name appeared after an elaborate sequence of steps. Easter eggs differ from cheat codes in that they typically have no gameplay function — they exist purely as developer self-expression or tributes.

Software that replicates the hardware behaviour of one computing system on another, allowing software designed for the original system to run unmodified on different hardware. Game console emulators model the CPU, memory bus, graphics processor, sound hardware, and input systems of the target machine. High-accuracy emulators like Higan (Super Nintendo) and PCSX2 (PlayStation 2) prioritise exact hardware reproduction over performance, while others optimise for playability. Emulation is legally and ethically complex: the software is generally legal, while distributing copyrighted ROMs is not.

Numerical data describing how many frames each action in a game requires, typically expressed as startup frames (before the action is active), active frames (when it can hit), and recovery frames (during which the character is vulnerable). Frame data is most critically important in fighting games, where the difference of one or two frames determines whether a combo is possible and whether a move is "safe on block." Public frame-data spreadsheets and in-game training modes now expose this data officially; before internet resources, it was extracted by frame-counting VHS recordings.

The practice of systematically searching a game for programming errors that produce unintended behaviour — out-of-bounds movement, memory corruption, frame-perfect collision bypasses, or duplication exploits. Glitch hunters use emulator debugging tools, memory viewers, and frame-advance to isolate the exact conditions that trigger an error. Their discoveries feed directly into speedrunning routes and TAS improvements, and have produced some of the most technically sophisticated community documentation in gaming.

A playable character in a game — typically a fighting game or sports game — who does not appear in the standard character select screen and must be unlocked through specific conditions or codes. Hidden characters create long-term engagement beyond the main roster and reward dedicated players with exclusive content. The practice was pioneered by Yie Ar Kung-Fu (1985) and Street Fighter II (1991), and became a key feature of fighting games through the 1990s. Unlockable characters were largely replaced by DLC characters in the online era.

The invisible geometric shape — usually a rectangle or series of rectangles — attached to a character or object that the game's collision detection uses to determine whether two objects have made contact. A hitbox may be smaller or larger than the character's visible sprite; deliberately undersized hitboxes on player characters make them easier to control in dense environments, while fighting games use separate hitboxes for attack and vulnerability zones to allow aggressive "active frames" without immediate counter-vulnerability.

The total delay between a player pressing a button and the corresponding action appearing on screen. Input lag accumulates from multiple sources: the controller's wireless or wired latency, the console's processing time, the display's internal image-processing pipeline, and the game's own input polling rate. Competitive players and speedrunners typically use CRT monitors or modern displays with "game mode" enabled to minimise lag; the difference between 1 frame (~16ms) and 4 frames (~66ms) of lag is perceptible and affects timing-critical gameplay.

A disc image file — a binary copy of an optical disc (CD, DVD, or Blu-ray) stored as a single file. In gaming, ISO files are ROM equivalents for CD-based and DVD-based consoles: PlayStation, Sega Saturn, Dreamcast, GameCube, and PlayStation 2 games are commonly distributed as ISO or related formats (BIN/CUE, GDI, CHD). The name derives from the ISO 9660 filesystem standard for CD-ROMs. ISOs are larger than cartridge ROMs due to disc capacity; a PlayStation 2 game ISO can be several gigabytes.

The input sequence Up, Up, Down, Down, Left, Right, Left, Right, B, A — created by Konami programmer Kazuhisa Hashimoto as a personal testing shortcut during the NES port of Gradius (1986) and accidentally left in the final cartridge. Its most famous implementation is in Contra (1988), where it grants 30 lives and enabled millions of players to finish an otherwise brutal game. The code has been referenced in over 100 Konami titles and has spread far beyond gaming into websites, films, and cultural references as a universal shorthand for secret knowledge.

A Japanese compound word combining "kuso" (crap) and "ge" (short for "game"), meaning a game of exceptionally poor quality. Unlike a simple bad game, a kusoge typically has a quality so entertainingly terrible that it becomes worth experiencing ironically — a Japanese analogue to "so bad it's good." Famicom-era Japan produced a notable catalogue of rushed kusoge, and the term has been adopted by Western retro gaming communities. Certain kusoge, like Big Rigs: Over the Road Racing, have developed cult followings precisely because of their brokenness.

A portmanteau of Metroid and Castlevania (specifically Castlevania: Symphony of the Night), describing a subgenre of action-platformer built around a large, interconnected map where progress is gated by specific abilities or items acquired during play. The player backtracks through previously explored areas as new powers open routes that were inaccessible on the first pass, rewarding thorough exploration and map literacy.

A graphics mode exclusive to the Super Nintendo that affine-transforms a flat tile layer — rotating, scaling, and translating it in real time to create the illusion of a 3D plane. Mode 7 does not produce true 3D geometry; it projects a 2D layer at an angle, producing the perspective effect used in F-Zero's racing surface, Super Mario Kart's track, and the world map in Final Fantasy VI. The effect was technically impossible on the Sega Genesis, making it a key SNES differentiator.

A technique in 2D games where multiple background layers scroll at different speeds to create an illusion of depth. Objects depicted as distant move slowly while objects depicted as near move quickly, mimicking the parallax effect observed when looking out a moving vehicle's window. The SNES and Genesis both supported multi-layer parallax; games like Sonic the Hedgehog and Super Metroid used it extensively to give flat environments a sense of spatial dimensionality.

A genre derived from Rogue (1980), characterised by procedurally generated dungeons, permadeath (losing all progress on death), and turn-based tile movement. The Berlin Interpretation — a community-defined set of criteria — codifies the "true roguelike": ASCII or simple tile graphics, grid-based movement, and complex systems that interact in unpredictable ways. Every run generates a different dungeon layout, making mastery a function of systems knowledge rather than level memorisation.

A game that borrows roguelike elements — procedural generation, run-based structure, and permadeath — but relaxes the strict Berlin Interpretation criteria, often incorporating persistent unlocks, real-time action rather than turn-based movement, or meta-progression that carries across deaths. The roguelite is commercially dominant over the "pure" roguelike; games like Hades and Dead Cells use procedural generation to create replayability while allowing players to permanently strengthen their character between runs.

Read-Only Memory — in gaming contexts, a digital file containing an exact binary copy of a game cartridge's ROM chips. A ROM file preserves the complete software content of a cartridge and can be loaded by an emulator to run the game on modern hardware. The legal status of ROM files is contested: dumping a ROM from a cartridge you own occupies a legal grey area, and distributing or downloading ROMs of games still under copyright is infringement in most jurisdictions. Preservation organisations argue ROMs are essential for archiving games that are no longer commercially available.

A side-scrolling action genre in which a player-controlled character moves forward through levels while shooting horizontally and jumping over obstacles, maintaining constant forward momentum under relentless enemy pressure. Contra (1987) established the genre's definitive template: large humanoid characters, multi-directional aiming, and screen-filling bosses. The genre is closely related to the SHMUP but distinguishes itself through on-foot ground-based movement rather than vehicle flight.

An emulator feature that captures a complete snapshot of the emulated hardware's state — CPU registers, RAM contents, GPU state, audio buffers — to a file, allowing the player to restore that exact moment at any time. Save states are not a feature of original hardware; they exist only in emulation. They are invaluable for preservation testing and TAS creation, and controversial for casual play: they enable progression through games originally designed around lives-and-continues pressure but fundamentally alter the difficulty contract those games were built on.

The horizontal dark lines visible on CRT televisions between rows of phosphor pixels, produced by the electron beam's discrete scan pattern. Scan lines are a physical property of CRT display technology, not an artistic choice; they became aesthetically associated with retro games because all games before the early 2000s were designed to be displayed on CRTs. Modern displays render each pixel at full brightness without gaps, which some players find harsher than the soft, scan-line-filtered image that developers originally intended.

A contraction of "shoot 'em up," a SHMUP is a game in which the player controls a vehicle or character that moves through a field of enemy fire, shooting back to survive. The genre divides into vertical scrollers (Galaga, 1942), horizontal scrollers (R-Type, Gradius), and "bullet hell" or danmaku games (Touhou, Ikaruga), where the screen is flooded with elaborate patterns of projectiles that demand memorisation and precise movement.

A soft reset returns a game or console to its initial startup state via software — typically by pressing a specific button combination on the controller — without cutting power to the hardware. On the SNES, the standard soft reset sequence is L + R + Start + Select simultaneously. Soft resets were important before battery saves became universal, as they allowed quick restarts without physical manipulation of the hardware. In speedrunning, the soft reset is used to restart a run without the full console boot sequence, saving several seconds.

A subgenre of action RPG defined by the design philosophy introduced in Demon's Souls (2009) and refined in Dark Souls (2011): high difficulty calibrated around pattern recognition, sparse and cryptic narrative delivered through item descriptions and environmental storytelling, and a resource-loss mechanic that punishes death without ending the run. The term is now applied broadly to any game sharing this difficulty philosophy and feedback loop.

A playthrough of a game completed in the fastest possible real-world time, often exploiting glitches, sequence breaks, and optimised movement that fall outside the game's intended play path. Speedrunning has a formal competitive infrastructure: Speedrun.com tracks world records across thousands of games in multiple categories (Any%, 100%, Glitchless). Charity marathons like Awesome Games Done Quick have made speedrunning a broadcast spectacle, with runs routinely watched by hundreds of thousands of viewers.

The hardware ability to resize a sprite in real time, enlarging or shrinking it to simulate depth or produce special effects. Early arcade hardware like Sega's Super Scaler boards (OutRun, After Burner) used dedicated scaling chips to create the illusion of 3D movement by enlarging approaching sprites and shrinking receding ones. The technique was computationally expensive on home hardware; its quality was often a key differentiator between console ports of scaling-intensive arcade games.

A recorded game playthrough created using emulator tools that allow frame-by-frame input editing, save-state rewinding, and slow-motion — producing a theoretically perfect run that no human could execute in real time. TAS runs demonstrate the absolute performance ceiling of a game; they reveal glitches and routes that human speedrunners then study and attempt to replicate partially under normal conditions. TASVideos.org is the central archive for the format. TAS runs are clearly labelled as tool-assisted and are not considered legitimate human records.

Music composed in a "tracker" — software that presents music as a vertical pattern grid where each column represents a channel and each row represents a unit of time. The format originated with Ultimate Soundtracker on the Amiga in 1987 and became the dominant method for composing music on the Amiga, and later for PC demo scene productions. MOD, S3M, XM, and IT are common tracker file formats; tracker music is notable for embedding both the composition and the instrument samples in a single small file.