There's this yellow guy who lives in a yellow castle, and he's on a quest for a gleaming chalice. He's a total square, and no one could argue he's drawn with nuance or complexity. But his adventures represent a milestone in videogames. The yellow guy navigates complex mazes, hunting for objects that appear in random locations. He does battle with three dragons, each with distinctive personalities. He tracks down keys required to unlock impassable gates, all while dodging a thieving bat that's itching to pilfer from him. The yellow guy can even uncover a hidden room that contains a secret message laid down by The Creator himself.

I am of course describing the epochal game Adventure that Warren Robinett created in 1979 for the Atari 2600 console. Robinett was 26 when he programmed the game, entirely by himself, on an HP 1611A microprocessor. It looks low-res and dated now, but Adventure was among the most ambitious and complex games of its day.

It also was incredibly influential. Robinett essentially created the console adventure game, and pioneered several videogame conventions that are now so common that we take them for granted. Robinett is not unlike the early filmmakers who hit upon techniques like the cut and close-up that would become the fundamental grammar of cinema. Adventure was made in the era of Space Invaders, when game worlds existed within a single screen. Robinett created the idea that a game could take place on a series of screens, each representing a discrete location. If you steered your avatar off the left side of the screen, it would reappear in the next room on the right side of the screen. "I didn’t set out to make the videogame world bigger than a screen, but I had to," he tells me. It was part of the challenge he had set for himself, and he took great satisfaction in solving it.

Robinett explained how he made Adventure in a session at the Game Developers Conference. The game, he says, was inspired by a visit to Stanford Artificial Intelligence lab, where he spent several hours on a mainframe playing Colossal Cave Adventure by Willie Crowther and Don Woods. It was a pure text game ("YOU ARE STANDING AT THE END OF A ROAD BEFORE A SMALL BRICK BUILDING.") built around exploration and inventory management. Robinett resolved to adapt it to a console.

Making It Seemed Impossible

That seemed impossible on its face. The Atari 2600 was designed for graphics-intensive games like Missile Command and Asteroids. The controller was a directional joystick with a single button. "Also, Colossal Cave required hundreds of kilobytes of ROM," Robinett says. "The Atari 2600 had 4K." He would have to vastly condense and simplify the game.

The first step was translating the game from a purely text experience to a purely graphical one. Robinett cleverly reduced environments, characters, and objects to instantly recognizable, simple icons. Except for the deadly enemies. They look more like giant waterfowl than dragons. "I've become attached to my Duck Dragons," he says. "If I ever do a sequel, it will be Return of the Duck Dragons."

Robinett built subroutines into the characters that gave them distinctive behaviors. The subroutines continued even when characters were offscreen in one of the 30 different rooms. [Thirty different rooms! It boggled the minds of kids who got the game for Christmas in 1979.] The offscreen action made the game world feel even more like a real place, and all sorts of emergent situations arose from these subroutines. For instance, you could be devoured by a dragon and trapped in its stomach, only to see that thieving bat fly in, pick up that dragon, and flit around the game world with the two of you in tow. "That wasn’t intentional," says Robinett. "It resulted from the fact that it was a true simulation."

Beyond dealing with the constraints of the console, Robinett had to battle his bosses, who initially discouraged him from tackling so ambitious a project. But when they saw a working prototype, they pressed him to make it a tie-in for the upcoming Superman movie. He ignored their demands. "Sometimes you have to fight for your ideas," he says.

Somehow, Robinett crammed the entire game into the constraints of an Atari cartridge. "I even had 15 bytes of RAM left over,” he says. “There was room to have three more dragons if I had chosen to do so, but it seemed to be working pretty well. I guess that’s what what you’d call game balancing nowadays."

He Gave Us the First Easter Egg

Instead, Robinett used some of that space to build a secret room accessible only through an elaborate series of steps. The room contained the game’s only text CREATED BY WARREN ROBINETT. It is generally considered gaming's first Easter egg. Robinett didn’t tell anyone about it, and left Atari soon after finishing Adventure. "I thought of it as a self-promotion maneuver," Robinett tells me. "Also, I was pissed off. Adventure sold a million units at $25 apiece. Meanwhile, I got a $22K a year salary, no royalties, and they never even forwarded any fan mail to me." (The Easter egg, by the way, was first discovered by a 15-year-old in Salt Lake City. His letter to Atari is priceless.)

Last week's appearance at GDC was karmic payback for all the fan mail Robinett missed out on. His presentation was met with thunderous applause, and Robinett was mobbed by fans. A Google engineer peppered him with intricate questions about his code and his data structure, pulling up a video on his laptop to demonstrate a specific flicker effect he wanted to know more about. Robinett patiently explained the tech, pausing occasionally to shake hands and pose for photos. Then he autographed the grateful engineer’s printout of the disassembled code for the Duck Dragon sprite.

A graphics design lead at AMD gushed to Robinett about playing the game as an 8-year-old. He was too young to memorize the patterns of the maze, and terrified of being trapped by the dragons as he traversed it. "Adventure was the first survival horror game," he said.

A computer engineer and professor from Brazil asked Robinett to autograph his copy of the book 100 Greatest Console Video Games: 1977-1987, in which Adventure is the first entry. The fan thanked Robinett profusely as he clutched the book to his chest.

"Your game," he said, "Is … everything to me."

It's all a bit surprising to Robinett, who left the game industry in the early 1980s, moved to North Carolina and has worked in other fields ever since. It's only recently that he’s come to learn there is ongoing interest in his groundbreaking game.

"This is really gratifying," he says Robinett. "I'm so glad it's not forgotten."