The home cartridge

Twenty-six mechanics originate in these eight years, the densest concentration in the dataset relative to the number of games shipping. Space Invaders introduces Lives and Continues alongside the Coin-Op Difficulty Economy, which is the first time monetization directly authored a difficulty curve. Asteroids adds Wraparound Topology and the Persistent High-Score Table. Defender decouples the camera from the playfield with the Continuous Scrolling Playfield, arguably the most consequential spatial idea before 3D, while Battlezone puts the camera inside the world at eye level and Adventure turns the world into a graph of rooms. Rogue alone accounts for five entries in 1980: procedural levels, experience points, permadeath, hit points, and the food clock. Everything the arcade cannot do, the home computer does — Wizardry adds Character Classes, Castle Wolfenstein gives enemies the capacity to fail to see you, Lode Runner ships a level editor in the box, Ultima III starts a clock the player does not control, and Elite computes eight galaxies from a seed. Fiction arrives late and sideways, through Pac-Man's interludes and Dragon's Lair's timed prompts.