In video games, a level (also referred to as a map, stage, or round in some older games) is any space available to the player during the course of completion of an objective. Video game levels generally have progressively-increasing difficulty to appeal to players with different skill levels. Each level may present new concepts and challenges to keep a player's interest high. In games with linear progression, levels are areas of a larger world, such as Green Hill Zone. Games may also feature interconnected levels, representing locations. Although the challenge in a game is often to defeat some sort of character, levels are sometimes designed with a movement challenge, such as a jumping puzzle, a form of obstacle course. Players must judge the distance between platforms or ledges and safely jump between them to reach the next area. These puzzles can slow the momentum down for players of fast action games; the first Half-Life's penultimate chapter, "Interloper", featured multiple moving platforms high in the air with enemies firing at the player from all sides. Level design Level design or environment design, is a discipline of game development involving the making of video game levels—locales, stages or missions. This is commonly done using a level editor, a game development software designed for building levels; however, some games feature built-in level editing tools. History In the early days of video games (1970s-2000s), a single programmer would develop the maps and layouts for a game, and a discipline or profession dedicated solely to level design did not exist. Early games often featured a level system of ascending difficulty as opposed to progression of storyline. An example of the former approach is the arcade shoot 'em up game Space Invaders (1978), where each level looks the same, repeating endlessly until the player loses all their lives. An example of the latter approach is the arcade platform game Donkey Kong (1981), which uses multiple distinct levels to progress a storyline; as Mario (originally called Jumpman) tries to rescue Pauline from Donkey Kong, each level ends with Kong fleeing with Pauline and then Mario having to complete a different level each time, until he finally confronts Kong. 1983's Lode Runner was one of the first titles to ship with a level editor. Its designer, Doug Smith, reputedly paid neighborhood children to design levels for the game. The same year, the multiplayer dungeon crawl Dandy was released,