The colour card and the cursed attic

Jet Set Willy, by Matthew Smith, came out in March 1984 from Software Projects. It is the sequel to Manic Miner: Miner Willy has to tidy up the mansion after a huge party before he can finally go to bed, and to do so he makes his way through 60 screens ^[1]. It spent more than three months at the top of the charts and was the best-selling home computer game of 1984 in the UK ^[1].

The box contained a card with 180 colour codes, in a grid of 10 columns by 18 rows. On loading, the game named a square on the grid and would only start with the right combination of four colours ^[2]. The tape was easy to copy; the card, at a time when colour copying at home was difficult, was not ^[1]. The system was invented by Alan Maton, who patented it in the UK, and programmed by Matthew Smith ^[2].

Well, that's just a little something we put in to make it a bit more difficult.

According to Chris Cannon, of Software Projects, the protection "was thrown together in about ½ a day, more as an afterthought" ^[2]. In 2017, the researchers John Aycock and Andrew Reinhard studied it in the academic journal Internet Archaeology: the card measured 61 × 98 mm, to fit in the cassette box, and some codes were repeated, with only 125 of the 180 being unique ^[2]. They also report that the publisher offered a replacement to anyone who was colour-blind or lost the card, but none of those who complained ever sent the game back ^[2].

The card was not the worst of it. In the Your Spectrum office, after finding about 45 rooms, the players noticed that certain rooms killed Willy the moment he entered. On the phone, someone at Software Projects asked whether they had visited The Attic, and replied: "Well, that's just a little something we put in to make it a bit more difficult." The magazine was not convinced: "The feeling our end is that it's a bug being turned into an asset" ^[3].

It really was a bug. An arrow in the attic had the wrong vertical coordinate and, when drawn, wrote outside screen memory, over the data for other rooms ^[4]. After a visit to the attic, the chapel guardians would station themselves at the entrance to the kitchen and other rooms, and the game could no longer be finished ^[3][4].

In July 1984, Personal Computer Games published the official fixes: load the game without letting it start and type in a few POKEs, among them POKE 59901,82, which puts the arrow in the right place ^[5][4]. The magazine noted that Software Projects was "clearly embarrassed", and the publisher pointed to the enormous pressure to release the game without delay ^[5]. The prize for finishing the game already had its winners: Ross Holman and Cameron Else, from London, who worked out on their own how to fix the program ^[5].