Fangame
Fangames are video games made by fans based on one or more established video games. Many fangames attempt to clone or remake the original game's design, gameplay and characters, but it is equally common for fans to develop a unique game using another only as a template. Though the quality of fangames has always been variable, recent advances in computer technology and in available tools have made creating high-quality games easier.
Fangame development
Fangames are either developed as standalone games with their own engines, or as modifications to existing games that "piggyback" on the other's engines. Each approach has different advantages, as standalone games are generally accessible to larger audiences but may often be more difficult or time-consuming to develop.
Standalone games
Generally, fangames are developed using pre-existing tools and game engines. The Unity engine and Adobe Flash allow fans to develop standalone games, as do other programs such as Game Maker, Construct (game engine), RPG Maker, or any of the Clickteam products (such as The Games Factory and Multimedia Fusion 2).