Maze Algorithm: Duncan Muirhead & Paul
Allen Newell (Programmers)
Entombed: Steve Sidley (Programmer), & Tom
Maze Chase then Zoomie Zombie
One of the more overlooked titles in the Atari 2600 library,
Entombed is an interesting little maze game with a simple
concept: Don't get trapped (entombed if you will) in the
scrolling maze. With its muted graphics and simplistic
gameplay, Entombed didn't make much of a splash upon its release
in late 1982 and was quickly forgotten (being one of U.S. Games
last releases didn't help). This is a shame because as
simple an Entombed looks, it can really be a lot of fun.
Entombed started out life as an experiment by Duncan Muirhead
and Paul Allen Newell to develop a random maze generating
algorithm for the 2600. One day after work they decided to
see if they could create a endless maze generating algorithm that
always had a exit. Over a few beers they came up with an
elegant yet deviously complex algorithm that most accomplished
their goal. The code also allowed for changing the
difficultly of the maze on the fly and an asymmetrical maze, but
sometimes created mazes that were unsolvable or too simple.
Happy with their new algorithm Paul showed the code to his
management who wanted to turn it into a game. The problem
with this was that the code took up most of the free processing
time of the 2600 and there really wasn't much room for adding
actual gameplay elements. Still, management insisted that it
be turned it into a game one way or another. Paul continued
to tinker with his maze game but was pulled off to do higher
priority projects such as Towering Inferno and Scramble for the
Vectrex. Paul planned on eventually finishing the Maze game,
but left Western Technologies before this could happen.
The original maze algorithm
(note the asymmetrical maze)
After Paul left, he continued to work with Western
Technologies as a contractor. After finishing up Towering
Inferno (in which he used some of Maze code for room and layouts
and flame placement), he was directed by WT management to create a
stripped down version of his Maze game (only keeping the maze
generating algorithm) to turn over to programmer Steve
Sidley. Steve was then tasked with turning what he described
as "A basic maze generating routine having been partially written
by a stoner... when he was drunk and whacked out of his brain" (a
bit of an exaggeration) into a workable game. Steve took the
simplified maze generating algorithm (called MINOTR7 at this
point) and set out to make it into an actual game.
So what did Steve add to make Entombed into a proper game?
The first thing Steve added was an enemy (in the form of zombies)
that the player would occasionally encounter in the maze.
There are two different types of zombies in Entombed: Blue and
Orange. Blue zombies can only move through open passages
like the player can, but orange zombies can move through
walls. Steve also added the 'Make-Break'.
Make-Breaks are tools that allow to player to either make a wall
(to block blue zombies) or break a wall (when you're trapped in a
dead end). The player starts with one Make-Break but can
pick up more in the maze. The idea for the Make-Break
actually dates back to Paul's unreleased Maze game, but in that
version the player always had the power instead of having a
limited number of uses. If the player is touched by a zombie
or scrolls off the top of the screen they will lose a life.
In the one player mode the player scores one point for each
section of maze they traverse through (there are five sections in
each maze), but in the simultaneous two player variation there is
no scoring and each player simply tries to outlast the
other. Steve also updated the player graphic and added some
fixes to the maze generation algorithm which were designed to
prevent repeating patterns.
While Entombed may have been forgotten for the last few decades,
the game was recently thrust back into the spotlight when two
university researchers (John Aycock and Tara Copplestone) decided
to take a closer look at the maze generating algorithm and write a
based on their findings. This sparked a bit of renewed
interest in the game and in researching old game algorithms in
general including the New
Yorker Radio Hour doing a podcast on Entombed. While
it may not be the most original game on the 2600 (Steve was
somewhat hamstrung with what he could do with the existing code),
Entombed is definitely worth a play or two. The two player
variation the potential to be a fun retro themed party game.
A quick note on the confusing names and dates of the prototypes
listed below. Paul's original unreleased maze game was known
by various names during development (Maze, Amaze, Minotaur, etc.)
but the file names were always called MAZx where x was the version
suffix (starting with MAZ1 and culminating with MAZV).
These files were given more descriptive names when they were
archived in 2003. Maze02jun8 corresponds to MAZV, which the
final version of the game that was created during Paul's original
time at Western Technologies. Later when Paul was tasked
with stripping down his game to serve as a base for Steve Sidley
to develop Entombed he started naming the files after
Minotaur. Starting with MINOTR (which corresponds to
MAZV/Maze02jun82) he then applied some timing fixes that Dave
Hampton had added to his Towering Inferno code and created MINOTR1
which corresponds to the Maze22jun82 prototype. The MINOTR7
prototype was the final version in the Minotaur series which was
the version that was given to Steve. Zmbi28oct82 is
the last known WIP version of Entombed.
For more information on Maze and the development of
Entombed, please check out Still
Entombed After All These Years: The continuing twists and
turns of a maze game by Paul Allen Newell, John Aycock,
and Katie M. Biittner. They have done extensive research
on the subject and many of the findings on this page were pulled
directly from their amazing article.
Polaroid of the original
maze generating algorithm in action. The 'Forbidden'
meant that Paul was not supposed to work on it until Towering
Inferno was finished.
||Maze02jun82 / MAZV / MINOTR
|Original Maze game with 42
||Maze22jun82 / MINOTR1
|Timing update to Maze02jun82
||Stripped down maze generation demo based on MINOTR2
to 2600 Software