Yars' Revenge hit store shelves in May 1982. It's the best-selling original Atari title for the 2600 console, and frankly one of the strangest visually. Its creator, Howard Scott Warshaw, managed to develop some very interesting effects, but the pillar of pixels and colors that functions as the "Neutral Zone" is what steals all the attention. A detail ignored by many players is that inside that pillar the game's code is hidden, and on the Retro Game Mechanics Explained channel they ask whether it's possible to decipher it…
The first step to mastering Yars' Revenge is nothing other than reading the manual… because nobody understands what to do at first. The game began development as a potential port of Star Castle, but the technical limitations of the Atari 2600 led its programmer Howard Scott Warshaw toward a story about mutant humanoids (the Yars) that evolved from the common fly and are under threat from the Qotile. The Yars' "revenge" is for the destruction of one of their planets, Razak IV.
All these details come from the official material that accompanied Yars' Revenge (a comic, a song, and even an audio drama), and from Warshaw's own comments. For example, "Yars" and "Razak" are a play on words inspired by the then-CEO of Atari, Ray Kassar. But the most important thing is right there, in the center of the screen every time a game starts: The code of Yars' Revenge, hidden in the Neutral Zone.
Is it possible to decipher the code of Yars' Revenge hidden on the screen?
The Retro Game Mechanics Explained channel mentions that Warshaw "almost" had a legal problem with Atari for manipulating his code that way, but besides using scrolling in both directions, he also applied X-Y changes and random colors, adding that "if anyone could get the code from all that, then they deserved it".
The initial analysis from the video reveals that the graphics of Yars' Revenge flicker, because the console can't draw all elements at the same time. If the Neutral Zone is active (along with the Destroyer Missile and the Zorlon Cannon), the Qotile Shield disappears, and vice versa. If we focus completely on the Neutral Zone, some patterns start to emerge: the animation spans 128 frames, but taking the flicker into account (frame on, frame off), the entire loop is 256 frames, or 4.3 seconds.
Editor's note: Headphone alert.
With additional adjustments to the graphics (always on an emulator, since it would be impossible to capture that level of detail using the console's original RF signal) and a good dose of "Exclusive or", Retro Game Mechanics Explained managed to isolate 254 rows (or bytes) with seven-bit representations… and that's a problem that splits into three parts: There's a hidden bit (the so-called least significant), we don't know the orientation with certainty… and half the code is missing.
From the 15-minute mark, the video becomes much denser on a technical level, but that doesn't make it any less interesting. On the contrary, it's a forceful demonstration of the programmer's creativity, who made the most of the Atari 2600's limited resources, and of the knowledge that Retro Game Mechanics Explained has to interpret code, even when it's incomplete. In fact, Warshaw himself stopped by the comments section, and felt "happy and relieved" to see that his method of obfuscating the code managed to withstand such an analysis.
