mwenge / defender
The source code can be compiled into an executable that you can then run in Windows or Linux. You can also compile it into the 11 rom files that would have been loaded onto the arcade cabinet's ROM board. Today, these rom files can be used to play the game in an emulator such as MAME.
Once you've built defender you can now use the rom files in the `redlabel' directory to play defender on MAME. If you're on Ubuntu you can also install MAME with apt:
The source code for Defender in src was originally retrieved from https://github.com/historicalsource/defender. It is the Motorola 6809 assembly language source code for the 'Red Label' version of the game.
There were four versions of the game released: White Label, Blue Label, Green Label, and Red Label, in that order. Each release was a circuit board with the compiled code split across a number of different ROM chips, also referred to as 'ICs'. This image of the Red Label ROM board from Scott Tunstall's site gives you an idea of what such a board looks like:
If you compare this image to the file listing for the Red Label roms you'll notice that the missing chip on the board corresponds to a missing file defend.5:
