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The Making Of Robotron: 2084

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Robotron: 2084, the arcade hit by Eugene Jarvis and Larry DeMarr, remains one of the best twitch shooters of all time. It’s innovative control system is still seen in games today, while it’s tightly honed gameplay continues to test everyone who comes across it. Here Eugene Jarvis explains the creation behind his arcade masterpiece.

It’s the early Eighties and Defender has been released to much acclaim. Designer Eugene Jarvis, who initially based his iconic horizontal blaster on Space Invaders and Asteroids, is playing another early title when inspiration strikes for perhaps his most famous creation – Robotron: 2084. “Berzerk! was amazing, but I got frustrated playing it, because you had to move towards enemies to shoot them. As they closed in it was hard to kill them without them killing you,” remembers Eugene. “One day, I realised if you hold the fire button down, your player remains stationary, but you can still move the joystick to fire bullets.”


Every level of Robotron is an assault on the senses.

For Eugene, this was a ‘Eureka!’ moment. “A lightbulb went off in my head – ‘the joystick fires the bullets’. I then thought why not have two joysticks – one to move and one to fire? It was so obvious – such a natural control method!” In one fell swoop, Eugene devised a breakthrough gaming mechanic for his new title, and one that perseveres to this day – although in typically modest fashion, he notes that if he hadn’t thought of it, “someone else would have”.

The control method was duly worked into a game Eugene had already started, which, like Berzerk!, was based on Robots. “Initially, you had to get robots to collide and destroy each other, but that was too passive – after playing Defender and Stargate for two years, you gotta kill things,” he laughs. “So that’s when the ‘shooting joystick’ came into play.”

By utilising a dual-joystick approach, Eugene says his game became more life-like, enabling you to retreat from a foe while shooting at it, adding freedom in terms of firing. However, there was little freedom in the environment, with Robotron confining you to a single screen – a retro decision even in 1982, especially following Defender’s scrolling universe. Robotron’s beauty is in its confinement and intensity,” argues Eugene, likening it to Space Invaders, but with enemies approaching from all angles. “When we first tried this, it really grabbed our attention – there were no safe areas, because foes were coming at you from everywhere.”


There’s a story about saving humanity at Robotron’s core.
There’s also a lot of shooting.

With such an escalation of warfare, other components were needed. First, a stronger enemy required a stronger player, to ensure balance of power, hence the plentiful projectiles the player’s weapon spews. Secondly, a rescue theme was introduced, transplanted from Defender. “This was added so the game wasn’t just about killing everything,” says Eugene. “We got to tell a story, with different characters, and used rescuing clones of the last human family for progressive scoring.” He explains that once you’re up to 5,000 points, you become motivated to try for more, since 25,000 points provides an extra life. “The character of the game changes – you become almost suicidal in order to grab humans!”

Further gameplay richness is provided by Robotron’s cast, which grew as the game was developed. First up were static, deadly Electrodes and simple-minded GRUNTs (Ground Roving Unit Network Terminators), a foe that closely paid homage to the inspirational Robots. “GRUNTs were designed to make the player feel surrounded and trapped from all sides,” says Eugene, adding that GRUNTs are simply programmed to take the shortest path to you – something that rapidly amplified the game’s intensity. “I’d been working on the game for a few days when we got rudimentary GRUNTs going, and we said, let’s play with ten. That was kinda fun, so how about 50? How about 100? It was killer, and the funny thing was that with the dual-joystick thing, we ended up blowing a path through GRUNTs when surrounded, returning to Berzerk!-style shooting in the direction you’re moving!”


Later waves spawn this deadly tanks that can cause all sorts of issues for you.

In a sense, the Electrodes and GRUNTs shifted Robotron towards its main source of inspiration in another way, too. Although Robotron’s single screens lack walls, myriad enemies almost create a maze, albeit one that continually shifts; enemies appear randomly on screen at the start of each level, and the player has two seconds to take in the playfield and decide where to go. Another interesting element, according to Eugene, is the GRUNTs’ speed. “They go towards you at an ever-accelerating pace, but are never faster than you. This gives you a chance, but GRUNTs cut corners and always close in on you.”

According to Eugene, the next enemy designed, indestructible green Hulks that kill humans they collide with, were also inspired by Berzerk!. “They’re Robotron’s Evil Otto. It’s cool having an indestructible enemy – they add interest to the game, because you have to go around them, although we helped the player out a bit by enabling you to fire at Hulks to temporarily keep them at bay.”

At this point, no enemies fired projectiles of their own, and so the levitating Enforcer was devised. “We liked the idea of a levitating robot, and it was also cheaper than animating something walking,” laughs Eugene. The Enforcer also continued a thread from Defender, providing the illusion of enemy intelligence via projective algorithms. “The simplest thing you can do is calculate the angle from the enemy to the player and shoot directly, but if the player’s in motion, the enemy always misses,” explains Eugene. “Therefore, we added random direction – instead of shooting directly at the player, Enforcers shoot within ten pixels of your location, and therefore might still hit you.”

brains - about to die

Grab as many women and children as you can as they’re worth lots of points.

With some projectiles taking into account the player’s velocity, thereby aiming at where you’re heading, and having random acceleration to make their paths curve, you might swear they’re sometimes seeking you, but that’s not the case – they’re just using parameters available when shots are made. Interestingly, because of the ‘cheap form of division’ used to determine distances between enemy and player, Enforcer shots always arrive in the same time-frame, regardless of distance travelled. “The further you are from an enemy, the faster the shots get, and so it’s almost safer to be nearer the enemies,” explains Eugene. Although counter-intuitive, this is a gameplay mechanic seasoned players exploit – as Eugene says, “If you try running into corners, life can be short, especially since projectiles that hit walls just follow their lines, funnelling into corners.”

Eugene also decided to make Enforcer spawning rather different to that of GRUNTs and Hulks, utilising the concept of a monster generator, a key component of later games like Gauntlet. “The Spheroid was devised to deposit little embryos of Enforcers around the screen. Shoot the ‘mother’ and offspring not yet birthed also perish,” explains Eugene. “But if you die, the generators reappear and birth more. You can get into this steady-state situation where you keep dying and they keep generating – it’s like you can never get them out of the way, unlike in Defender, which always has a fixed number of enemies.”

To keep the balance of power intact, Eugene decided to enable players to shoot enemy projectiles, adding an element of defence, but it wasn’t long before another foe was added: Brains. These were considered master controllers, preying on humans, turning them into brainwashed Progs that incessantly hone in on the player. “Their defence is a cruise-missile projectile that seeks you out, but in a random fashion,” says Eugene. “It sometimes goes away from you and comes back, seeking a random spot around you, often killing you in the process (laughs), but this adds suspense. As they come at you, you’re not sure what’s going to happen.”

You can read the rest of our Making Of Robotron: 2048 in issue 60. Buy it now from GreatDigitalMags.com

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