Flappy is a puzzle game by dB-Soft in the same vein as the Eggerland series and Sokoban that is obscure outside of Japan. It features Flappy, a somewhat mole-like character who must complete each level by pushing a blue stone from its starting place to the blue tile destination.
Flappy first appeared on the Sharp X1 home computer in 1983. This debut was soon followed by with conversions to a number of popular Japanese computers in the early 1980s, including the NEC's line of PCs and the Fujitsu FM series. As a puzzle game, it was well suited to these early systems since it didn't require a tremendous amount of graphical sophistication. Ports for the MSX computer line and the Nintendo Famicom were released in 1985. DB-Soft produced a sequel with more difficult puzzles called King Flappy for the benefit of anyone who managed to clear the original 200 levels. A Nintendo Game Boy port was released exclusively in Japan in 1990 and was published by Victor Musical Industries. Over time, Flappy has continued to see many graphically improved upgrades, such as on the Windows platform and on several mobile phone devices. It was released on Japan's Virtual Console in 2007.
Two officially-unreleased variants of Flappy, Floppy and Beyond Floppy, were programmed by Greg Hale and Ted Cohn for the Apple II platform. Floppy featured special names for each of the game's levels. Included with both Apple II games was an editor which allowed the user to create their own custom levels.
Source: Wikipedia, "Flappy", available under the CC-BY-SA License.