Defender is an arcade classic and one of the most successful titles in what is now known as the golden age of arcades. Released in 1980, it was the first video game co-designed by Eugene Jarvis and was part of a team of four coders who developed it for the pinball company Williams (after the success of Space Invaders, wanted to enter the arcade market).
You could say that Defender was created by pinball designers, mainly because it was very fast and very difficult. Jarvis is a genius designer, but he was also used to designing products where a high level of player skill and a desire for mastery were taken for granted. Their games never lost that quality, though they softened over time: Robotron 2084 was still incredibly difficult, while NARC and Smash TV soiled your lives as if it were nobody’s business.
Anyways: the Defender source code has been posted to Github. This is the code for the "Red Label" version of the game, one of four versions distributed in the arcades, and includes some funny notes about the montage of Mr. Jarvis himself (or "Dr. J").
TO ASSEMBLE THE DEFENDANT TABLE
RASM PHR2, DEFA2, DEFB2, AMODE0; -X (OTHER CREF SYMBOL OVERFLOWS)
RASM PHR2, SAMEXPA7
RASM PHR2, DEFA2, DEFB2
TO GET DIAGNOS, CHAIN ALL.CF
LOAD IT ALL AND THEN REJOICE IT WORKS
(NOTE: PLEASE NOTE TO LOAD ORDER
SEARCH FOR THE SELECTED BLOCK SHIT
DR J. 21/01/81
Retired coder James Cuff has been scanning the code and found some interesting remnants of Williams' pinball legacy, with tickets for a ball timer and the number of balls played (of course, no balls in Defender) .
You can also see the history of Williams as a pinball company. Balls played and ball timer. Here are many other fun codes to cut and paste. Use the code Luke 🙂 pic.twitter.com/sdGXR88C2iJuly 13, 2021
Cuff also found some funny notes in what appears to be the game's "attract" mode code (the demonstration that slot machines play to attract players). First it's "It's time to blow up the enemy" and then a line later "Explode the bastard", before "Pass the man". Some of the items were "For Eugene", before the machine had to "make it faster" and then "put it back on".
I lined up Eugene Jarvis ’current company to see what he thought of all this and will update with any answers. His name may not be familiar to younger readers, but this guy is one of the greats of the arcade, though, as he admitted in this paper, old interview with Gamasutra, "I always try to duplicate the success of Defender. It's like I'm doomed to never have that level of success again and I keep dreaming."
But he’s probably a fan. "I always think that MAME has also been a wonderful thing when it comes to preserving the legacy of games. The graphics have continued and the game has continued, but it's fun to watch and play (old games) and see the business history. It's a history lesson that's great entertainment in itself. "