Petscii Jetski by Nick Montfort & Jesper Juul
for the Basic 10 Liner Contest 2020


Move your jetski left and right by pressing 1 and 2. Avoid pressing any other keys.

First, reach the left edge to score a point. Then cross the screen to the right edge, and continue back and forth across the screen. Your score is displayed at the top. It appears on the left or right depending upon where you should go next.

Your jetski will speed up each time you make it across the screen and back.

Letters are safe.

Get a score of 10 to win the game.

Full Explanation of the Code

We have provided a detailed discussion of this 10-line BASIC program in an 11-page technical report from the Trope Tank, TROPE-20-01, “A Full Explanation of the Petscii Jetski Code.” This document is free and issued under a Creative Commons BY-SA license.

The Concept

We consider Petscii Jetski to be a visual poem as well as a videogame. We sought to create a game that is playable, replayable, and indeed exhilarating.We also wanted to require the player to “read” what is being displayed on the screen. The player has to distinguish alphabetical characters from other characters, some of which are similar: the zero is not a letter ‘O’ and the cross symbol is not a letter ‘X’. Although the game doesn’t present any words, except by chance, it does require reading on this low level.

Better Ways to Play

This web edition gives you a nice glimpse of how the game works, but sound does not work very well and there are other issues with in-browser emulation. If you wish to play on your recently-manufactured computer, we recommend having VICE (the Versatile Commondore Emulator) directly installed on your system, and using this 64 disk image of Petscii Jetskii. Even better, use that disk image with a hardware edition of the Commodore 64!
Running here in VICE.js by Richard Janicek — based on VICE by Martin Pottendorfer, Marco van den Heuvel, Fabrizio Gennari, Groepaz, Errol Smith, Ingo Korb, Olaf Seibert, Marcus Sutton, Kajtar Zsolt, AreaScout, Bas Wassink, Michael C. Martin, Christopher Phillips, and David Hogan — based on the Commodore 64 by Yash Terakura, Shiraz Shivji, Bob Russell, Bob Yannes, and David A. Ziembicki — using the 6510 processor by Bill Mensch and Chuck Peddle. This game is written in BASIC version 2 by Ric Weiland, Bill Gates, Paul Allen, and Monte Davidoff — based on the BASIC programming language by John Kemeny, Tom Kurtz, and collaborators at Dartmouth College.