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The Making Of Boulder Dash

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Boulder Dash remains one of gaming’s most enduring franchises. Since being released in 1984, it’s gone on to spawn numerous games and has inspired many others. Here creator Peter Liepa remembers how it all began.

The word ‘classic’ is bandied about all too frequently in the world of videogames, often awarded to titles that are ‘merely’ very good. A classic is a game that lives on through the ages, touching each generation of gamers anew, but still remaining a firm favourite with those who encounter it over the years. One such game is Boulder Dash, which since its release in 1984 on the Atari 400/800 has gone on to inspire numerous conversions and sequels. Despite modern versions of the game becoming increasingly complex and lacking the frenetic nature evident in Peter Liepa’s original, the gameplay remains largely unchanged: you explore caves, dig through dirt and collect gems, avoiding obstacles and various nasties.


Carefully dig so that you can funnel the boulders.

Surprisingly, the initial ‘spark’ that birthed Boulder Dash came from another programmer: Chris Gray. “In the early Eighties, a friend introduced me to videogames, and I thought ‘I can write a game’. I bought an Atari 800 and contacted a local publisher,” recalls Peter. “They introduced me to Chris Gray, who’d submitted a demo written in BASIC.” Peter remembers that the demo was incomplete, and needed to be translated into assembler to be commercially viable, which he considered “a reasonable first project to get my feet wet”. However, when Peter spent time with the game, he decided it wasn’t worth converting. “The demo was named Pitfall and played just like The Pit, although Chris denied any knowledge of that game,” explains Peter. “In Chris’s version, the action was very hard-coded: rocks followed pre-determined sequences, and there wasn’t much for the player to do.” Contrary to popular belief, Chris’s input largely ended at that point. “He must have thought he’d have the role of creative director, but it didn’t work out,” says Peter. “We lived far apart, and our occasional meetings weren’t helpful or productive, especially since I took off in my own direction very early on.”

This direction, according to Peter, wasn’t inspired by any existing games. Although Boulder Dash has certain similarities to The Pit, Dig Dug and Mr. Do!, Peter states he wasn’t influenced by them, and that his game grew out of coding the physics for dirt and rocks: “The game’s original graphics were crude – just squares, circles and spaces – and what evolved was a cellular automaton that encoded the basic physics of what was to become Boulder Dash. I used a random generator to set up screens full of rock and dirt that I could dig through using my joystick.” With this basic system, it became clear that digging through dirt and figuring out how to get through configurations of rocks was an entertaining experience. “But this was a long way from being a game, I needed some way of keeping score, and so I added jewels. And I had to add risk, so now you died if you were hit by a rock.” In addition to puzzle interest, the game was beginning to appeal to emotions like greed and fear. “In my memory, all this took just a few days,” says Peter. “Although in reality things must have accumulated over weeks and months: adding sound effects, additional ‘actors’ like fireflies, butterflies and amoebae, static elements like walls and titanium walls, and so on.”


Boulder Dash first appeared on the Atari 8-bit before moving to
other popular home systems.

Crucially, every element added to Boulder Dash was done for a specific reason, ensuring the creation remained tightly honed. “If you reduce the game to the currency of jewels and death, you’ll understand how various characters arose, either as a way of generating more jewels (amoebae, butterflies, magic walls) or killing Rockford (fireflies, butterflies),” explains Peter. “Some of the other factors also played a role, but perhaps more implicitly than explicitly. For example, more passive characters like the brick walls, titanium walls and exits play a constraining or navigational role.”

The game mechanics weren’t the only thing being developed; when a potential publisher complained that the graphics weren’t striking and that the digging character wasn’t recognisable enough, the original cave size of 40 by 24 character blocks (with diminutive elements a mere eight pixels high) was ditched. In its place arose a chunky, rugged graphical style, with each entity composed of four character blocks. The digging character, Rockford, acquired personality and a somewhat strange appearance, as Peter explains: “The main requirement for Rockford was that he was able to run, but with so few pixels, you have little to work with. Once I’d drawn the feet, legs, torso and arms, what was left over made for a fairly large head, hence Rockford ended up looking like a Smurf. As for personality, when you stop moving the joystick, the game pretty much stops. To bring life back to those moments, I had Rockford blink and tap his feet. I’m proud of this effect, because it gives Rockford autonomy of his own – he’s not just a puppet that you manipulate. I’ve seen this technique used in subsequent games, but I’d like to think I was the first to use it.”


This intermission screen gives you one chance to complete it properly.

With larger caves, scrolling was introduced. Instead of using a flick-screen approach or having the screen religiously follow Rockford, Peter gave the scrolling in Boulder Dash a kind of inertia, with it only kicking in when Rockford approached the edges of the screen and catching up when Rockford stopped moving. “Instant scrolling was too jarring, especially when Rockford moved in a complicated trajectory or one square at a time, so the idea came about that scrolling would start only when Rockford got close enough to an edge of the screen for it to be necessary. That way, scrolling would be minimised. This changed the gameplay as well, because you have less visibility into the areas you are approaching; you don’t see them until you get closer to the edge of the screen.”

Remarkably, the development of the actual caves and puzzles took relatively little time. “I never created a cavern editor,” says Peter. “Rather, I developed a simple cavern definition language that allowed me to draw points, lines and rectangles consisting of characters, along with specifying random densities. After this, it was easy to come up with caves on demand.” According to Peter, he never believed that having difficulty levels was that important – they were added primarily to fit into the conventional mould of a videogame. “The levels differ by the allotted time limit for each cave and the overall density of things like rocks. Also, the first cave in the game was something I designed when First Star asked for an easy introductory level – a ‘granny’ cave that anybody could be successful in, so called because your grandmother could sit down and finish it!”

You can read the rest of our Making Of Boulderdash in issue 27. Buy it now from GreatDigitalMags.com.

Retro Gamer magazine and bookazines are available in print from Imagineshop

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