A fan game is a game created by the fans of a work that is explicitly based on said work. In terms of the Super Smash Bros. series, this results in low-budget, non-profit games that imitate the gameplay of the series, while simultaneously allowing fans to create and use characters and stages without having to hack an existing game. Fan games tend to be created in environments such as Flash, Game Maker, or Clickteam Fusion, and as a result, are almost exclusively sprite-based. Although the games often feature trademarked characters, settings, music, and other such aspects, their lower production values and presentation causes fan games to be considered legal under parody or fair use laws.
Projects that involve modification of the actual games in the series can be considered a type of fan game. Such projects, however, are often considered separate from typical fan games, due to their differing development; fan games are generally created from scratch, whereas mods involve modifying an existing game.