Defender Arcade Game Logo

Not long after getting my first PC in 1994, I started to explore emulators. I don’t remember exactly which was the first, maybe it was NES or SNES, but before the 1990’s was over I’d amassed quite a large collection of emulators. These days I rarely play a game that wasn’t released in the 20th century!

I was always intrigued how these old games were made. Almost all were written in Assembly language and over the years I collected together a list of links to dissasemblies for various games. Some are long gone, some moved to different URLs, and others unfortunately completely vanished from the web.

Although there are some efforts to gather video game source code/disassemblies in one place, such as the Video Game Preservation project, it’s still difficult and time consuming to find many of these disassembly projects.

Rather than let my own list rot away on my hard drive, I’m sharing it here for anyone else who is interested in this kind of thing.

Source Code and Disassembly Collections

These projects document and preserve the original source code and documented disassembly of many old and not so old arcade and computer games.

  • Video Game Preservation (VGP) Github repositories which include games from the 1970’s through to the 2000’s, and mostly quite well known releases like, Defender (Aracde), Doom (PC), Duke NUkem 3D (PC), Zork (PDP-10), Alien Breed 3D (Amiga), Sim City (PC).
  • Historical Source Github repositories which include many titles from the VGP collection but also some slightly unusal entries like Gloom (Amiga) and Microsoft GW-BASIC (PC).
  • Computer Archeology hosts a number of famous arcade games such as Asteroids, Moon Patrol.
  • BJARS Atari Archives hosts a large collection of Atari 2600 game disassemblies.
  • Atari Museum has the original source code for popular Atari 7800 titles like Ms. Pac Man, Dig Dug, and Joust.
  • Level7 BBC Micro game disassemblies including Exile, Knight Lore, and Jet Set Willy.
  • C64 CSDb includes the source code for a handful of Commodore 64 games, including Boulder Dash and Load Runner.

Arcade Disassemblies

Arcade games were around a good few years before home computers and host some of the most famous video game titles. Many of the games on this list have very good source annotations, making them interesting reading.

The following lists cover home computers and consoles from the late 1970’s through the early 1990’s.

Atari 2600

The venerable Atari 2600. The first major home console may seem a little crude by today’s standards, but back in the day this was a great little machine – my cousins had the machine and I always looked forward to visiting them. The graphic may be super low resolution, but there’s still some great gameplay to be had. Here’s a few of the more classic titles, and even a couple where the original source code was made public.

ZX Spectrum

This was the computer of Great Britain in the 1980’s, and a computer which I had myself. For all it’s faults (colour clash!) it was a great gaming computer. It produced some of the greatest home computer games of the 80’s and kick started the gaming industry in the UK. No wonder then that it’s popular with people creating annotated disassemblies.

Commodore 64 (C64)

I got my first Commodore 64 in 2018! Although I knew someone at school who owned a VIC 20, I never heard of anyone owning a C64 let alone getting the chance to use one. Still, 35 years on and I now have my own, and they’re a great little machine. There’s a huge community around the C64 and this includes some great disassemblies for you to browse.

BBC Micro

As a Brit, I used a BBC Micro at school, but I never had the opportunity to play any games on this computer. Still, this is where Elite originated, so it’s certainly a machine with some great gaming capabilities.

  • Crazee Rider (1987, Superior Software Acornsoft), original source code.
  • Elite (1984, Acornsoft), original source code.
  • Exile (1988, Superior Software Audiogenic), disassembly.
  • Galaforce (1986, Superior Software Acornsoft), original source code.
  • Jet Set Willy (1986, Tynesoft), disassembly.
  • Knight Lore (1984, Ultimate Play The Game), disassembly.
  • Sabrewulf (1984, Ultimate Play The Game), disassembly.

Apple II

Atari 7800

This is not a machine I’ve used myself, but these titles are worth including here as they are all the original source code as released by the Atari Museum.

  • Centipede (1987, Atari Corporation), original source code
  • Commando (1989, Sculptured Software), original source code
  • Dig Dug (1986, GCC), original source code
  • Food Fight (1987, GCC), original source code
  • Galaga (1986, Atari Corporation), original source code
  • Joust (1987, GCC), original source code
  • Ms. Pac-Man (1986, GCC), original source code

NES (Nintendo Entertainment System)

Nintendo Entertainment Systems weren’t popular in the UK, but the guy at my local record shop (Harry’s Records!) had one behind the counter. Those were great days; buying fantastic rock vinyl (Pearl Jam’s Ten, Manic Street Preachers Generation Terrorists; both picture disc albums, which I still have!), then sitting playing Tennis and Super Mario for a couple of hours! I finally bought my own NES in 2019 and also have both those games.

Games are getting much bigger by this time so it’s impressive to see these disassemblies being attempted.


By 1994 I’d moved from the Amiga to the PC. It’s surprising how few 80’s PC games have been disassembled. Check out the Video Game Preservation project for lots of source code releases, including Doom, Spelunky, Hexen, Decent, Allegiance, etc.

  • Digger (1983, Windmill Software), original source code.
  • Donkey Kong BAS (1981, Bill Gates), original source code.
  • Gorilla BAS (1991, IBM corporation), original source code.
  • Sim City (1989, Maxis), original source code.

Game Boy / GBC / GBA

SNES (Super Nintendo Entertainment System)

Sega Mega Drive / Genesis

Another console with very few disassemblies, but at least Sonic the Hedgehodge has been done, what more do you need from the Mega Drive!

  • Sonic 1 (1991, Sega), disassembly.
  • Sonic 2 (1992, Sega), disassembly.