Robotron: 2084 was a pioneer of its day, and it remains just as fun to play now as it was when it was released in arcades back in 1982. Today at GDC the game's designer, Eugene Jarvis, talked about the game's development as part of the conference's series of classic-game postmortems.

Jarvis opened up asking how many people in the audience had played the game. Unsurprisingly, nearly everyone raised their hands. He went on to say the term postmortem seems a little morbid, like the stench of death is in the air. Unlike many of those games where so many things go wrong, Jarvis says that everything seemed to go right during Robotron: 2084's development.

When work on Robotron began, Jarvis had just finished work on Defender and Stargate. He wanted to try something new, and knew that robots were cool. He liked the game Chase on the Commodore PET computer, where players lured ASCII robots into mines. Another inspiration was the arcade game Berzerk. The game featured an 8-way joystick, mazes, seven or eight enemies at a time, and what Jarvis said were frustrating controls. Everything killed you, and you could only fire one shot at a time. He likened his fascination with it to what players were experiencing more recently with Flappy Bird – people enjoy getting their asses kicked.

Jarvis' new game, which was still being called "Robot Wars" internally, would take advantage of great audio quality, comparatively advanced hardware, and two joysticks, one for movement and another for firing. The game would run on a 1MHz Motorola 6809 8-bit processor, with 32 kbytes ROM for the game, 256 bytes of RAM for the high-score tables, and a 19" CRT display. Many of the game's sound was generated by using special tools that essentially allowed programmers to punch numbers into a formula. The team would keep what they liked, and scrap the rest. Jarvis says the insert-coin sound is what happens when you entered 0 in all of the fields.

Moving onto a more philosophical tone, Jarvis pointed out the human legacy as he sees it. Pollution, climate change, nukes, wars, mass extinction, etc. Humans decide to create Robotrons, to replace the imperfect with the perfect. The Robotrons take over, and it's not great. Machines are capable of designing other machines quickly – the natural selection that would let people grow a sixth finger to use an Xbox controller, Jarvis jokes – would take too long. It's the survival of the smartest, and we're not it. The humans aren't considered efficient by the Robotrons, and they attack their creators.

Jarvis says that creating classic arcade games meant that they had to focus all on gameplay, challenge, difficulty ramping, and more, since relying on realism was out of the question. Designing games then wasn't like scripting movies or even contemporary games. In the '80s, they'd take on more of what we call a game jam approach. They'd start with an idea, build a prototype and play it, and keep iterating. Development was programmer-centic then, so Jarvis said much of the visual design was what he jokingly refers to as "programmer art."

As far as the design itself goes, Jarvis says Robotron is about confinement. Unlike Stargate, which allowed players to fly around the world at maximum velocity, players were locked into a single screen, surrounded on all sides. Your character is the result of some kind of genetic-engineering mishap, which game you superpowers. You have to save the last human family. The first Robotron enemy was the electrode, which were essentially mines that would sit passively and kill you if you touched them. The grunts were next, humanoid robots with minimal IQ that seek the player. Grunts would increase their velocity as their numbers were culled.

At first, just like Chase, players couldn't fire a weapon. It wasn't fun. They tried dual-stick shooting, and it was fun. They encouraged accuracy by making it so players could only have four shots active on screen at a time. It still wasn't tough enough, so they increased the number to 127 or 128 grunts. Jarvis said the game was fun after three days. Then they had to "finish the soup." They decided to add a bigger variety of Robotrons, each of which would add something unique. Some might have better offensive strengths, while others would be defensive powerhouses. Putting humans into the game gave players a reason to venture out into danger, since they rewarded players with progressively higher point values that could lead to 1ups.

The hulks were the next enemy types. Like the Incredible Hulk, Robotron's Hulks were green and huge. And like Berzerk's Evil Otto, he was indestructible. To balance things, he'd move randomly, sometimes toward the player, other times to points elsewhere on the screen. Players could knock him backward temporarily by firing at him. It wouldn't do any damage, but it would fend him off long enough to escape or away from a potential human rescue.

Enforcers were added afterward. To make things easier with the programmer art, he wasn't animated. Instead, he floated around like R2-D2, spawning the hoop-shaped spheroids. After that came the brains, enemies with giant brains. Brains sought out humans, and once captured would turn them into an enemy called the progs. Brains could also fire a cruise missile, that was the only projectile that would seek players. The brains are also part of something called the Mikey Bug. Instead of seeking out the nearest human, the brains inadvertently only target Mikey. If savvy players can keep Mikey alive, the remaining humans are safe, creating the potential for a huge extra-life payoff at the end of the round. They needed one last enemy type: the tanks. They shot projectiles that would reflect off walls.

Jarvis said the game was a great example of how players assign more sophistication to the game's A.I. than was really there, thanks to the element of random elements.

He wrapped up with a gameplay video, and the thunderous blips and booms filled the auditorium,