Entombed is an Atari 2600 game, where the player and their team of archaeologists get stuck into a ‘catacombs of zombies’. The game, among many other old releases, are explored by ‘video game archaeologists’ to learn how the early days of video gaming came about, and to find secrets that can help modern programming problems of today. In trying to unearth how this video game was created, video game archaeologists John Aycock and Tara Copplestone stumbled upon a bigger mystery than they expected.
Entombed’s main gameplay mechanisms are the catacombs, a down-ward scrolling and two dimensional maze that players have to navigate to escape zombies. The game generates the maze design randomly and on the fly, where players never traversed the same maze twice. This is where the mystery lies, on how the game decided its maze designs, as BBC detailed:
It turned out that the maze is generated in a sequence. The game needs to decide, as it draws each new square of the maze, whether it should draw a wall or a space for the game characters to move around in. Each square should therefore be “wall” or “no wall” – “1” or “0” in computer bits. The game’s algorithm decides this automatically by analysing a section of the maze. It uses a five-square tile that looks a little like a Tetris piece. This tile determines the nature of the next square in each row.
How? That’s the fascinating part. The fundamental logic that determines the next square is locked in a table of possible values written into the game’s code. Depending on the values of the five-square tile, the table tells the game to deposit either wall, no wall or a random choice between the two.
Aycock and Copplestone have tried retro-engineering the table. They looked for patterns in the values to try and reveal how it was designed, but this was to no avail. Whatever the programmer did, it was a stroke of mild genius. During their research, Aycock and Copplestone were able to interview one of the people involved in the game’s production, Steve Sidley.
He too remembered being confused by the table at the time. “I couldn’t unscramble it,” he told the researchers. And he claimed it had been the work of a programmer who developed it while not entirely sober: “He told me it came upon him when he was drunk and whacked out of his brain.” Aycock tried to contact the programmer in question but got no response.
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