CODE & BOOKS

Atari 2600 · original game

Klakwall

A bat, a ball and a wall of bricks that will not wait. Every two and a half seconds the wall takes a step down the screen, and when it reaches the bat the game is over.

Download the game klakwall.bin · 4 KBSource codeThe book
Klakwall on the Atari 2600, score 0006, a wall of red, orange, green and blue bricks near the top, the ball in flight and the white bat at the bottom.
The attract mode, a few seconds in
Klakwall, score 0017, the wall lower down the screen with gaps in its front row.
The wall has taken nine steps, and the front row is going
Klakwall, score 0028, the wall close to the bat with many bricks gone.
Twenty-eight bricks, and a life gone

Klakwall is played with the joystick. The bat slides along the bottom of the screen; the ball bounces off it, off the side walls, and off the face of a wall of bricks at the top. Every time the ball strikes the wall it breaks the nearest brick still standing in that column, counting from the front backwards, and the score goes up by one.

What makes it Klakwall rather than something older is that the wall does not wait. Every hundred and fifty frames it takes a step down the screen. The sky above it grows, the space the ball has to work in shrinks, and when the wall reaches the bat the game is over. There is nothing to clear and nothing to win: there is a score, and there is how long you lasted.

When nobody is playing, the title screen plays the game by itself. That attract mode is also why every photograph of it in the book could be taken twice and come out identical.

Where it comes from

Written line by line in Atari 2600 Assembly:

  • Chapter 37: Klakwall: paddle, ball, an advancing wall, and the physics of a bounce · ch37/