Ghostbusters

01 · The game

Run a ghost-catching business, and end with more money than the bank lent you

In Ghostbusters the bank lends you $10,000 to start a franchise.¹ You spend it on a car and equipment, then drive round a city map to buildings where Slimers have moved in, trap them for fees, and bring the traps back to headquarters. All the while the city's PK energy climbs, the Marshmallow Man stomps on buildings, and two wanderers, the Keymaster and the Gatekeeper, head for the Temple of Zuul.

When they meet there, the bank checks your balance. Less than you started with ends the game. Otherwise the car goes to Zuul, where two of your three men must slip past the Marshmallow Man into the building. Finish with more money than you started with and the game gives you an account number that carries the money into the next game.

Play GhostbustersSee how a game goesExplore the city map

02 · The makers

David Crane's design, with help from across Activision

The game names one person. Its title screen says DESIGNED BY DAVID CRANE COPYRIGHT 1984, and the cassette manual credits nobody.² Crane had made Pitfall! for the Atari 2600 two years earlier.

Other roles come from later sources. MobyGames lists Adam Bellin for additional programming and Hilary Mills for graphics.³ Wikipedia and the C64-Wiki credit the music to Russell Lieblich, arranging Ray Parker Jr.'s theme.⁴⁵ Wikipedia, citing Retro Gamer 25 (2006), says the sing-along with the bouncing ball was added at the last minute by Garry Kitchen, Dan Kitchen, and Alex DeMeo.⁴

Who spoke the speech is not known. Asked about it in Retro Gamer, Crane said he did not clearly remember.⁶ He did remember the program: "I had written an audio digitiser and driver for the C64". The Music and speech tab shows how that driver works.

03 · Six weeks

A driving game already in the works became Ghostbusters

A film tie-in has to reach the shops while the film is still showing. Activision gave the game six weeks where nine months was normal, and Columbia Pictures supplied the script and some storyboards but no idea of what the game should be.⁴ Retro Gamer's interview with Crane captions it "Turned around in just six weeks".⁶

The answer was a game Crane already had in progress, Car Wars. As he told Retro Gamer in 2010, "Car Wars gave Ghostbusters the economy, the car customisation and the driving scene where the player could vacuum up ghosts."⁷ The code still reads that way: a bank balance that decides the ending, a shop that loads equipment into a car, and a road where the ghost vacuum is the only thing to do.

04 · Reception

Reviewers praised the sound, and it topped the charts

British magazines reviewed it at the turn of 1985, and the presentation was what they wrote about. In Personal Computer Games 14, January 1985, Chris Anderson wrote that "the presentation and initial impact of this program are unbelievable" and that "the music and speech could hardly be bettered". He added that the game "might not work, were it not for the fact that it succeeds so well in recreating the feel of the film".⁸

Your Commodore 7, April 1985, called it "impressively programmed" and "Recommended, even though you don't get a free Sigourney Weaver with every cassette". The magazine said the speech was "done using only the basic 64 sound chip filters: no additional hardware is required".⁹ The second half is right. The first is not quite: the code plays the speech through the sound chip's volume register, not its filters (Music and speech).

In the United States the newsletter Computer Entertainer had the C64 version at number 6 in its December 1984 top ten, under the headline "Ghostbusters Take Over Europe!".¹⁰ In the UK it topped the chart from January to March 1985.⁴

05 · Other versions

The C64 version came first

Ports followed for the ZX Spectrum, Amstrad CPC, Apple II, Atari 8-bit, MSX, IBM PCjr, Atari 2600, NES, and Master System, most of them made without Crane, and a budget re-release on Mastertronic's Ricochet label in 1988.⁴

06 · Inside the game

Explore how Ghostbusters works

Each tab takes one part of the game apart, from the game's own code.

• Play: the whole game, ported from its own code.
• Gameplay: the shop, the drive, the bust ($85D4), the Marshmallow Man, Zuul and its two endings, and the account number that saves your money.
• Controls: why the joystick goes in port 1, and the keys that work in play.
• Map: the city's buildings and their clocks ($73BD), PK energy, and the meeting at Zuul that ends the game.
• Graphics: every sprite in the game, unpacked from its own data, and the interrupt that draws each frame.
• Music and speech: the sing-along and five phrases of speech, played through ports of the game's own players ($93E1, $F080).
• Discoveries: an eighth piece of equipment nobody can buy, a phrase the game never says, four bugs, and an ending the guides get wrong.
• Source code: the whole game disassembled and annotated.