8- and 16-bit

Consoles get memory, and memory changes what a game can be about. Metroid's Password Continuation and The Legend of Zelda's Battery-Backed Save File let a game be longer than one sitting, which is what invents the campaign; Metroid's Ability-Gated Interlocked Map makes progression spatial rather than linear. Super Mario Bros. teaches players a physical vocabulary through Momentum-Based Platform Control instead of a binary one. Ultima IV proposes Branching Dialogue Trees and an Explicit Morality Axis in the same release, and Ultima VII gives its characters daily schedules. Street Fighter II's Chained Combo Strings begin as a bug and become a skill ceiling nobody designed. Dune II lands two roots at once — Real-Time Base and Unit Production and Fog of War — neither with a parent in this data. Doom closes the period with four separate entries: Networked Deathmatch, In-Game Automap, Selectable Difficulty, and Open Data Formats and Mod SDK, the last of which turns players into an unpaid apprenticeship pipeline whose graduates ship Counter-Strike and Defense of the Ancients.