The Development of Robotron

Is there a classic arcade game player out there that doesn’t like Robotron?

Released by Williams Electronics in 1982, it is the quintessential arcade shooter. Ferocious enemies, panic-inducing gameplay and sounds that match the action on screen like no other game of its time.

Having spent 18 months developing the wildly successful side-scrolling shooters Defender and Stargate for arcade manufacturer Williams, the small development team of Larry DeMar and Eugene Jarvis, otherwise known as Vid Kidz, had now moved to a tiny office in North Halstead Street, Chicago. They wanted to try something completely different for their next game. After some discussion, they decided to create a game based around robots, based on a hunch apparently, that “everyone thinks robots are cool, right?”

arry Demar and Eugene Jarvis, pictured here around the time of Robotron’s development

Working using two computer systems, one for software development (a Gimix 6809, based on a Motorola 6809 8-bit processor – state of the art for the time), and another for debugging, the pair knuckled down to work on what would become one of the true iconic games of the video game golden era:

Not the greatest picture, but this is the office where Robotron was developed. Note the two development computers, and cabinet on the right

Taking inspiration at the time from two other games, an obscure title called Chase on the Commodore PET system, and Stern’s wildly successful arcade title Berzerk, they quickly started work on a new project known at the time as Robot Wars.

The guts of a Gimix 6809. Running at 1Mhz, 56K and with dual floppy discs – it was cutting edge technology in 1981

Jarvis recalls his early memories of Berzerk:

I spent many hours at the controls of Berzerk. It was a nice simple game with a set of rules that made it a fun, engaging game. But I was really frustrated with the fact that you had to move towards something in order to shoot it.

Stern’s Berzerk

This was the primary influence in Robotron becoming a twin-stick game, (coupled with the fact that Jarvis was involved in a minor car accident at the time, resulting in a broken wrist):

Some guy jumped a red light and the shock of the impact through the steering wheel completely shattered my right hand. I was out for about six weeks. At the time, I loved Berzerk, but it was frustrating because my broken hand meant I couldn’t press the fire button any more. The limitations of the movement in that game were also annoying – you had to move towards the bad guy in order to fire a shot in his direction. So, both those things combined to give me the idea for a dual-joystick control where you could move in one direction and fire in another.

This dual-stick system, unique for its time, gave the player a sense of wielding awesome firepower – something they would need to combat the insane amount of enemies to be dealt with in Robotron. They looked to the code they had produced for Defender and Stargate; reusing some of the routines, sounds and sprites already developed, and began to come up with a concept of a game. Remember this was a time where there were no high-level computer languages, no operating systems (Windows hadn’t even been thought of yet), no tools, middleware or API systems – Vid Kidz had to “roll their own” back end programming tools and systems.

One of the key elements of Robotron compared to Defender and Stargate is one of player confinement. Given the way the game was taking shape, Jarvis quickly realised that with a game full of large moving sprites each with their own characteristics, it was going to be impossible to implement scrolling across multiple screens. Far from feeling limited by the hardware available at the time, Jarvis was inspired:

Designing videogames is all ABOUT limitation. It’s not about doing everything that’s possible, just because you can. It’s about finding some small subset of something that’s FUN and building on that. With Robotron, you’re stuck in this confined little space. That confinement is the key element in what makes Robotron feel the way it does. The constant feeling of being cornered and having to fight your way out of that corner – fight or flight. There’s no choice. You’re ALWAYS making a last stand.

This “last stand” that Jarvis refers to is further amplified by placing the player at the very centre of the screen at the start of each level. Unlike its contemporaries where typically the attack pattern tends to be top-down (as in Space Invaders for example), Robotron comes at the player from all directions. “Fight or Flight” is at Robotron‘s heart.

Robotron screenshot

Storylines are not something that early videogames are known for, but very early on, Vid Kidz created a backdrop for the game, to give the player a sense of context for the wanton onscreen destruction. Jarvis set Robotron in the future (the year 2084 to be precise) where humans, realising their faults and failings create a new species called Robotrons that are so advanced, man has replaced his own imperfections, with something supposedly perfect. But of course, there’s always trouble in paradise. The objective was:

You are the last hope of mankind. Due to a genetic engineering error, you possess superhuman powers. Your mission is to stop the Robotrons, and save the last human family: Mommy Daddy and Mikey.

The three humans. Mommy, Daddy and Mikey

This context of a basic emotional attachment to the game creates what is the key motivator within the game: risk vs reward. What set Robotron apart from its contemporaries, is this dual objective – killing robot enemies whilst saving human characters.

The uniqueness of Robotron arguably is the vast array of enemies and their individual behaviours. Let’s take a look at them. The first iteration of the game featured just two foes:

Electrodes. These static objects kill on contact, but can be destroyed by players
Grunts have minimal AI, but do seek out the player, and were designed to be cannon fodder, creating satisfying gameplay. As they are shot down, they increase in speed – adding to the oppressive nature of the gameplay

Demar and Jarvis thought about stopping there, playing around with different numbers of Grunts. At one point they had 127 Grunts on screen, together with a rule that stated only four shots from the player could be visible at any time on screen. It was fun for a while, but they wanted to add more action to the development soup. In order to ramp up the levels of player panic, additional enemies were designed. Each would have its own personality and ruleset. Inspired by the game of chess, they wanted a limited set of enemies that could create infinite variety.

The Hulks are indestructible moving walls that will kill not only the player, but also humans. The player can fend off hulks by firing at them, which will retard their movement
The enforcers (left) spawn out of Spheroids (right). Interestingly, they were apparently created out of the team’s frustration at having to write animation routines! To save time, they created a static enemy that literally floats around, targeting the player with deadly spark-like proectiles, programmed to fire in the direction of where the player was moving towards, rather than where they actually were at any one time
The Brains. These enemies seek out humans and reprogram them making them unsavable, and so limiting the player’s scoring opportunities. They fire projectiles that Jarvis describes as “mosquito-like”, constantly chasing and bothering the player. Taking them down before they reach their prey is essential to clear up the potential human bounty that appears within each of their waves
The Tanks have an ability to aim shots directly at the player, or to bank them off a wall (the only reflective projectiles in the game). The toughest of all the enemies, it is not uncommon to lose four or five lives just to get through a wave where they appear

With clever use of algorithms, Vid Kidz developed a system where levels are generated on the fly; creating new and fresh environments time after time. It is this “controlled randomness”, as Jarvis puts it, that makes Robotron so exciting to play – no two games are alike – there are infinite scenarios to deal with, using just two joysticks. Summarising the development process, Jarvis recalls:

It was built in six months. We designed all the graphics and animation in about two weeks, because there wasn’t much technology to play with. Then, we spent four out of the six months of Robotron’s development PLAYING the thing. We played the living hell out of it. We kind of got good – but not great – and somewhere along the way, we just developed a collective sense for the general feel and difficulty. I like to make things harder and harder for twenty or thirty waves and then roll things back a bit, recycle some stuff. It’s more fun to renew the player and give them a reward for everything they’ve been through, rather than just have the game get harder and harder.

Another key objective was to create a game that features different enemies within different levels. Placing every enemy on every wave would create a sense of monotony – something they wanted to avoid. Forcing the player to develop different strategies for each wave, as they progress through the game would create the draw in the arcades that would result in healthy cabinet sales.

The flyer announcing Robotron’s launch

And so, points are awarded for saving the humans, but players have to balance this objective with the key goal of each level – to destroy every enemy before being allowed to proceed. Players can clear a path to a human and go for the points available, but more important, however, is staying alive. These decisions have to be made within a split second. A subtle part of Robotron is the snapshot that players get at the start of each wave. A breif glimpse of what needs to be done for the next 60 seconds or so:

It’s that God’s-eye view that does it. It makes the game immediately tactical and strategic when you can see everything on-screen at the beginning of a wave in Robotron.

Which brings us onto the “Mikey” bug:

There’s a wonderful moment of tease at the beginning of the Brain waves, where you get to survey your plan of attack and drool over the potential points from the masses of humanoids wandering around. It’s like when you’re feeding a squirrel. You hold out a nut and the squirrel comes close and he’s thinking: ‘My God – this guy has a wonderful nut in his hand…’. But, he’s also worried that you could easily kill him, too. That’s the feel at the beginning of the Robotron Brain Waves – those two motivating forces pulling you in opposite directions. The lust for the rewards and the fear of the danger.

The Brains are programmed to seek out the nearest human to them. Due to a programming error on the first Brain wave, every one of them targets Mikey, ignoring the other “Mommy” humans on screen. If the player can keep Mikey alive without picking him up, and whilst destroying the Brains before they reach him, there are well over 100,000 points potentially available. However, if the player kills all enemies before sweeping up the other humans, the opportunity has gone. So whilst being an unintentional bug, the first Brain wave is actually a huge tactical opportunity to make significant progress during the early stages of the game. It is one of a few unique examples of an unintentional programming error that actually adds to the game.

Williams pushed the back story to Robotron at launch

Williams would often release promotional videos to coincide with the launch of their games in the early 80s. The Robotron promo is particularly well done and very much of its time:

When this video surfaced, Larry DeMar told an interesting story about one aspect of the gameplay shown; the death animation of the humanoids:

People have been commenting on the graphic in the video when the humans are killed in the game. It is not simply a matter of the video showing pre-release and the skull and crossbones being in the final release. In fact, the video was a great historical capture of a very small window of time. The game was originally designed with the skull and crossbones graphic that you see in the final game. When the game was being seen on test and in the showroom, pre-release, there were concerns raised that the skull and crossbones was too extreme for parts of the young audience that play our games (it is clear that this is way ahead of the Mortal Kombat era where these discussions were a lot more interesting). Joe Dillon, (a wonderful friend, amazing sales representative and revered VP of sales, loved by all in the industry, may he rest in peace) was insistent that the sales of the game would be measurably affected by the negative reaction to the skull and crossbones on the screen for the human characters. It was decided to replace the skull and crossbones with the X’ed out human you see in the video. The test games were updated and the video was shot. A very short time later, Eugene was so upset about the change, he made an 11th hour plea to Michael Stroll, who made the call to put the skull and crossbones back in the game. My memory is that this was done before production, however I know I’ve seen posts from people that have games with the X’ed out software.

Production numbers vary depending on who you talk to or what sources you read, but the consensus appears to be that around 23,000 uprights were produced. The cabinet came in three variants – upright, cabaret and cocktail:

The three Robotron cabinet styles: cocktail, cabaret and upright. A minor aside for those familiar with Robotron cabinets: note the quirky early side art design of the upright cabinet in this picture…

There is much more to digest regarding the development of Robotron. This article could easily be at least twice its length. I would highly recommend watching Eugene’s excellent talk about the game at the 2014 Game Developers Conference which I’ve linked to here:

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Jarvis and DeMar’s contributions to the game’s development are often cited by other developers as the reason they got into game creation. There is no question that Vid Kidz are the originators of high-action and reflex-based arcade games. Their influence on the video game industry cannot be underestimated, with Robotron being the pinnacle of their achievements – which is probably why the game is so revered by so many players and collectors today.

A player getting to grips with Robotron in 1982

Robotron has that secret sauce of “just one more go”. Every manufacturer of classic arcade titles was looking for this indefinable magic formula back in the day – the “X-Factor” that makes a game stand out from the crowd.

I recently managed to break through 400,000 points on the game (just!), but there are some monster players out there. If you have a spare seven hours in your day, take a look at David Gomez’s insane 101,000,000 point run in 2017, to see just how far this game can be mastered:

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I mean for God’s sake……

Anyway, for us mere Robotron mortals, there’s clearly many more quarters to be spent, which is no bad thing of course. As an aside, elsewhere on the blog, I recently restored a European Robotron upright cabinet, which you can read about here.

If Robotron is your thing, do consider joining the global Facebook page, Williams Defender Players Unite, where many great players and fans hang out and share strategies and tips on all Williams games, including Robotron. Annual “real world” meetups occur here in the UK, which attract some interesting characters!

L-R: with Larry Demar, World Robotron champion David Gomez and Eugene Jarvis at the 2018 and 2019 WDPU meetups at Arcade Club, England!

And finally, for a real deep dive into all things Robotron, I’d also point you in the direction of the excellent Robotron 2084 Guidebook, started by Mark Hoff many moons ago, now maintained by members of WDPU.

Credit: The Development of Robotron