Willy the Worm is a single-player, user-supported platform game created by programmer Alan Farmer of Charlottesville, Virginia and released for DOS in June 1985. It was followed by a sequel, Willy the Worm Part II: The Big Trip Home.
The game puts the player in control of a small invertebrate named Willy who must make his way along platforms and past various hazards in order to ring a bell that hangs at the end of each of the game's eight levels. Lethal hazards consist of cannon balls, which roll along the levels' platforms and ladders, and sharp tacks.
Willy has a limited amount of time to make his way through each level, as indicated by a bonus counter at the bottom of the screen which counts down from 1000 in increments of 10; when the counter reaches zero, one life is lost and the level restarts. Points remaining at the end of the level are added to the player's score. The player also earns points by jumping cannon balls (20 points) or collecting presents (100 points).
The four arrow keys control movement left and right along platforms or up and down ladders, and the space bar makes Willy jump. Other keys make Willy stop in place. The game uses PC speaker beeps for sound effects and ASCII characters as graphics and can run in either monochrome or color (blue and white) display modes.
The Willy the Worm Screen Editor, included with the game, allows players to design their own levels.
Source: Wikipedia, "Willy the Worm", available under the CC-BY-SA License.