Real Keen Player
Real Keen Player is the first game in the series of the same name. It is notable for including a level editor. The latest version dates to October 2000, a playable demo was released in June 1999.
It was followed by two sequels, Real Keen Player II and Real Keen Player III. In July 2005, the author stated that he will not spend any time on a fourth Real Keen Player, one reason was that the development of another 2D platformer would not offer enough challenge. However, he worked on a Windows port of Real Keen Player III in 2007, which was never completed.