From Populous Wiki
Levels are individual worlds in Populous, all having the same size. Worlds can have different textures (land, water and sky), and present different planets, where the player needs to destroy the enemy in order to conquer it. It is possible to play any level, both online and offline, against human opponents or AI. Also, by using the program World Editor, it is possible to create custom levels for either singleplayer or multiplayer.