Cambridge computing centre celebrates 40 years of Space Invaders

It created a worldwide phenomenon when it was released in 1978, creating a new type of video game.

Last weekend (June 2 and 3), fans of Space Invaders celebrated its 40th birthday at the Centre for Computing History on Coldham’s Road in Cambridge.

Created by Tomohiro Nishikado, millions found themselves hooked on shooting down hordes of aliens descending down a screen.

The retrospective, Space Invaders: 40 Earth Years, featured 40 versions of the game, a Space Invaders championship competition and a panel discussion.

The talk on the Saturday evening looked at the game’s technical, social and cultural impact, with a panel consisting of author Magnus Anderson, singer-songwriter MJ Hibbett and game developer Gary Antcliffe.

Jason Fitzpatrick, director of the Centre for Computing History, hosted.

He told the Cambridge Independent: “The talk went through the various aspects of the game – how it was developed, some of its unique characteristics, because there are things that Space Invaders has done that have never happened again...”

Jason, who remembers playing Space Invaders for the first time on the Atari 2600 console, says the real reason the game speeds up as play continues has nothing to do with making it more difficult – at least that wasn’t the original plan.

Instead, it had more to do with the processing power of computers at that time.

“It’s kind of a happy accident,” he explains. “As you’re drawing more and more space invaders on the screen, you have a loop to go through x number of times, so if you’ve got a screen full of 56 space invaders, you have to go through the loop 56 times – but as you shoot them, obviously they become less and it means the number of iterations through the loop becomes less, so it speeds up.

“It was more of a programming feature that causes it to speed up, but the developers thought it was good that actually it gets harder the further you go through the level so it was left in and became a very important aspect of the game.”

The technique used to add colour is another interesting story. “The screen is purely black and white,” says Jason.

“It is reflected off a mirror, so the picture you see isn’t the picture on the screen, but the mirror is only a half-mirror so you can still see through it as well.

“Behind the mirror is a cut-out of a planet and behind that is a fluorescent tube, and behind that is a semi-circular cardboard space scene. So when the tube comes on, it lights up the background and the black and white aliens float over that background.

“It’s a very specific look, one that hasn’t really been achieved since in that way. And to make the aliens themselves colour, there was a piece of coloured acetate along the bottom.”

Anyone for a game?