This document provides an introduction to level design. It discusses key concepts for level design including theme, enemy design, obstacle design, puzzle design, and placement. It explains why level design is important as it provides players with useful mastery of game mechanics, influences decision making, and teaches players about a game's mechanics. Good level design reduces tutorials through balanced progression using differences in scale and kind. The document also outlines the four-step "Kishōtenketsu" level design approach used by Nintendo for games like Mario 3D Land.