It was to be the last hurrah of the 16K ZX Spectrum, a fast and exciting platform game squeezed into a minuscule amount of memory. In Antstream Arcade’s latest developer interview, we chat with Stephen Cargill, co-creator of the brilliant Sir Lancelot.

The Game: Sir Lancelot
Developer: Stephen Cargill, Andrew “Arnie” Arnold, Ian Piumarta
Year: 1984
Platforms: C64, ZX Spectrum
Genre: Platform

Story: Sir Lancelot is on an important crusade to plunder a castle of its useful items and valuables. The brave knight jumps and runs throughout the 24 rooms of this towering stone construction, avoiding the castle’s denizens while picking up anything bright and shiny. One touch from an enemy will sap Sir Lancelot’s life – fortunately, he has four life restorers that instantly re-animate him so he can continue his critical mission.

Antstream Arcade: Hi Stephen! Was Sir Lancelot your first game?

Stephen Cargill: Hello! I’d written a few small demos and then put together what was an almost complete game in early 1984. I called it Attack Of The Mutant Micros, and it was Space Invaders, but the invaders were graphics of computer-related things such as an RM380Z and Sir Clive Sinclair. I’ve still got a cassette, and I really should get it ripped at some stage to see what it’s like!

AA: Yes, imagine playing it on Antstream Arcade! How old were you at this point?

SC: I started properly coding while doing my O-Levels, so around 16. I developed into games programming at 17 in the upper Sixth Form and became engrossed in it. I loved experimenting, the excitement of getting some code working and optimising it.

AA: How did the idea for Sir Lancelot come about? Presumably, you were a fan of Manic Miner and Jet Set Willy?

SC: I was a huge fan of those games; I’m amazed you spotted a resemblance! Arnie was involved with most of the design and ideas – we worked very closely together on it, and it just organically developed.

AA: Who was ‘Arnie’?

SC: Andrew Arnold. He and Ian [Piumarta] were both fellow students in Sixth Form. We all went into computing careers, but I was the only one to continue with games. Ian worked with me on the music for the game, and we got what I think is about sixty seconds of music into about 50-100 bytes of code by using maths rather than playing a musical score. Arnie and I worked together for a while after I left the games industry – he was also best man at my wedding.

AA: How long did Sir Lancelot take to create?

SC: I can’t remember exactly, but it was probably two to three months of part-time work. We were friends, so did the game alongside socialising, and it was done for our own fun – quite a lot of beer was involved! There was a period of polishing at the end with input from Melbourne House.

AA: Were you interested in ancient legends?

SC: A little, but I wasn’t a great reader. Most of the design probably came from Arnie as I was much more a programmer than a designer. However, as I’ve grown older, I’ve come to appreciate the world’s history more; countless incredible stories are out there, and I recognise quite a few games of the time that drew on them for inspiration.

AA: The main character moves very quickly, unlike Miner Willy.

SC: I think it was just a result of the animation frames and code speed. It did make it gripping to play, with a fast and exciting arcade feel rather than a slow and thoughtful puzzle. We were limited to the number of animated frames we could store because it had to fit into the 7K or so of free memory.

AA: Did you code Sir Lancelot on an actual Spectrum?

SC: Yes, I think we had two machines at the time. It was incredibly basic compared to modern development environments, but that’s how it was. I had to develop a 48K Spectrum to have the tools loaded and then put the tape image together. I vaguely remember monitoring memory, so it never exceeded the 32K memory boundary, but I had to have a real 16K machine to finally test it on. I used DevPac from HiSoft; they were a great little company.

AA: Did you consider naming the rooms, as in Manic Miner and Jet Set Willy?

SC: I don’t think so. That would have taken up too much memory – we really squeezed it down to the last byte.

AA: Talking of Jet Set Willy, that bird character Sir Lancelot turns into in a couple of levels looks very familiar…

SC: I don’t recall the origin of that, but we initially wrote the game as a group of mates just playing around, so I’m sure there was a lot of inspiration from the other games we played. From a coding perspective, changing to a different character is simple, as the graphics are already there. We probably did it to add a bit of variety to the gameplay and confuse the player.

AA: The game differs significantly from Jet Set Willy in that Sir Lancelot can’t die from falling.

SC: It makes the game easier, but it’s also a fundamental part of the gameplay in places. Sir Lancelot is challenging enough without adding more ways to lose a life!

AA: Were there any bugs or other issues?

SC: Probably, and lots of them! We were learning as we went: there wasn’t an internet, there weren’t many manuals about serious games programming, and there weren’t even bulletin boards for the Spectrum world. I used the Sinclair Microdrive, which was pretty unreliable, and you had to make sure you had a good number of backups, including on cassette.

AA: How did the finished game end up with Melbourne House?

SC: I wrote to several publishers, sending off a cassette with the almost-completed game, and Melbourne House had the best offer. I came down to a show at Earl’s Court in the summer of 1984 to finalise the deal. It was basis royalties, but then I joined them on a salary.

AA: Sir Lancelot received glowing reviews, including a Crash Smash in Crash magazine – that must have been a fantastic feeling?

SC: It was absolutely incredible. I’d initially started it as a fun hobby, so to get [Sir Lancelot] published and get a proper job from it was very exciting. I’ve still got that framed review and advert somewhere – I think I’ll get it back on the wall for a while.

AA: Looking back today, is there anything you’d have done differently with Sir Lancelot?

SC: Possibly some way of saving the level, perhaps printing out a code for your score and lives, but I’m never sure that’s a good idea on this type of game – part of the challenge is getting through it in one go. I don’t think I would have had any spare code space anyway. Squeezing it into 16K meant the game had to be very lean.

AA: On that note, by 1984, the 48K Spectrum was firmly established – why 16K?

SC: We didn’t think there was enough in the game for 48K and felt the 16K market was being neglected.

AA: Finally, Stephen, as your first published game, what did you learn coding Sir Lancelot and how do you look back at that time today?

SC: Sir Lancelot was the first program I really had to finish and polish. The final tweaking is often what takes time, and it can get a little tedious. But it needs to be done and does make for a better and more polished result. The computers were open, they started with a command prompt and had full manuals detailing the OS and programming language. Most people were self-taught, and although there were development teams, a lot of the early games were written at home, by one person, in a few weeks. It was a really good time for programming, quite pioneering, really.

Our thanks to Stephen for his time. For news of weekly game releases and information on our tournaments and new challenges, visit our Discord, There you’ll discover a vibrant community of Retro Heroes chatting about Antstream Arcade games, high scores and more. And don’t forget you can play the ZX Spectrum legend, Sir Lancelot, for free, on Antstream Arcade!

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This blog primarily written by Graeme Mason covers retro gaming and offerings of Antstream - and can be checked out at it's original published location of