Prince of Persia postmortem
GDC 2011: Jordan Mechner walks conference attendees through the arduous four-year process of creating his classic action adventure.
Who was there: Delivering the classic game postmortem for the original Prince of Persia at this year's Game Developers Conference was none other than its creator, Jordan Mechner.
What he talked about: After a prolonged audiovisual snafu, Mechner dove into his postmortem on the making of the classic platformer, which began in 1985. As a cultural reference point, movies such as The Goonies were hitting theaters and the VCR was just gaining steam. It was the summer after he graduated from college, and he was at home living with his parents in New York. And while his friends from Yale were off joining the Peace Corps or working on Wall Street, he wanted to make a computer game.
His first computer was the Apple II. The competitive field he was plunging into included Karateka (which he programmed in college), Flight Simulator II, and the Hitchhiker's Guide to the Galaxy. Karateka was a number one best-seller, he said, and the royalties let him pay off his loans from college. It gave him a buffer to figure out what he really wanted to do, he said, due to low confidence levels in what he was doing.
He then went back to his journals that he was keeping during college and referenced an entry from July 1985, which read, "Will there even be a computer games market two years from now?" He thought Apple II development might be on the fall. The other thing that was holding him back was a desire to become a Hollywood screenwriter in a vein similar to his idol Chris Columbus, who wrote The Goonies and The Gremlins.
He then described his sources of inspiration for Prince of Persia, which were Lode Runner and Castles of Dr. Creep, from 1983 and 1984, respectively. His high concept idea was Lode Runner combined with Karateka. From the cinema, he was particularly inspired by Raiders of the Lost Ark, specifically the intense opening scene. He wanted to make a game where if you just barely missed a cliff, you could grab on to the ledge, and if you fell, it would really hurt.
Another filmic inspiration was Thief of Baghdad, a silent movie from 1924. At Broderbund, Karateka's publisher, someone mentioned the story of Ali Baba as a good idea for a setting. Another source of inspiration was the rotoscope, where he would take individual stills from a film, trace them, and then use the product as a way to create animation.
For Prince of Persia, he filmed his brother running and jumping in a parking lot, which served as the basis for his rotoscope work. To do the filming, he said that he bought a VHS camera with his first credit card, for the hefty sum of $2,500, and then promptly returned it using the device's 30-day guarantee.
After this step, a year went by where he had to code the tools to make use of this footage. At the same time, he was negotiating a deal with Broderbund where he could get out of his parents' house and move to California to work out of the company's offices. Broderbund was eager to hire him, but they wanted him in-house to do their games. However, Mechner saw them more as a book publisher, and he wanted to retain his independence.
He then showed a journal entry from September 1986 that floated the idea of calling the game "Prince of Persia," though only in working title capacity. He figured the name would be OK until they figured out what the real title would be. A year after shooting the rotoscope footage, he finally took it to the next step, which involved buying a VCR with a clean freeze frame.
He would take a picture, frame advance, take another picture, skipping every third frame, to yield an eight-frames-per-second pace. Mechner then made a black-and-white Xerox of each frame, digitized them, and then made rough animations from them.
After getting the technical proof of concept, he then focused on game design. He started with getting the character running and jumping and then built the world out from there. Game design for him at this point involved getting the individual moving parts working, such as pressure plates and false floors. He then built a level editor, where he could pick up a set piece and place it.
Pinball Construction Set, created by recent Academy of Interactive Arts and Sciences Pioneer Award winner Bill Budge, was a key inspiration for this game design, Mechner said. His thinking at this point was that the level editor would be included on the game disk.
He said at this time, his job title was programmer, but he was also doing a lot of the design work. Because of this, things went very slowly. When he was working on tools, the game design wasn't advancing at all.
As an aside, Mechner said that around this time, Broderbund received a submission for Alexey Pajitnov's Tetris. Someone reverse-engineered the game in an afternoon, and that brought things to a screeching halt in the office. In the end, Broderbund decided not to publish Tetris, even though they were all addicted to it, because they felt it was something that only programmers would like.
Back to Prince of Persia, the game was starting to take shape, and he realized there would be other in-game movements that he would need that hadn't been filmed the first time. He was able to take advantage of a visit from his brother to rectify this situation. Though he was a year and a half older and eight inches taller, he was able to correct for this and recapture the footage.
In 1987, he felt the game was maybe six months from completion, and it would be out later that year. However, he then hit a big snag. During the summer of 1985, he had also spent time writing a screenplay, and that got picked up by a Hollywood agency. Work on the Hollywood project then took over his life, causing him to shelve Prince of Persia. However, he said he woke up one morning eight months on and realized that he still hadn't made a movie.
From there, he went back to work to finish his half-completed game. When he went back, he said that as he looked at the code, it looked to him as if it had been written by someone else. Eventually, he got back into the swing of things. The design of the game was still very much in flux, he said, as was the story, which at that point was far more complicated than what actually made it into the game.
Around this time, hard drives began to be, if not readily, at least somewhat accessible. Previously, he had been using floppy disks to store all of his code, and he would switch disks between computers to debug. However, the introduction of the hard drive dramatically increased the time that he could code and test.
The tradeoff for creating a fluidly animated character was that there couldn't be two onscreen at once. This was OK, he said, because it was an adventure puzzle game, not a combat game. However, one of his coworkers insisted that there must be an antagonist, and eventually Mechner realized that he could easily make the enemy by using much the same assets as the Prince, just by shifting a few pixels and flipping the color scheme. Thus, Shadowman was born.
In 1988, he realized that the game was getting close to completion, and while it was beautiful, it wasn't particularly fun to play. It didn't have that "I've got to keep playing" quality. "Your game is all about survival, and not triumph," one coworker told him, the same one who suggested bringing in an antagonist.
He said that he had lost sight of the basics. He went back and looked at Karateka. It moved left to right, and everything along the way indicated that the player was getting closer to his or her goal. He realized that POP lacked a lot of these qualities, such as clear goals and subgoals, clear visual indicators of progress, and setbacks and triumphs along the way.
Out of this, he reduced the scope of the game from 50 levels to 10. The progression became starting in the dungeon, working up to the palace, and then saving the princess. In this phase, he also dumped the idea of shipping the level editor with the game. However, because he had the editor, he was able to rebuild the levels quickly.
The next step was to implement swordfighting. To figure out how to make swordfighting exciting, he turned to his favorite childhood movies, such as The Adventures of Robin Hood (1938). He broke down what people were doing in every frame and then implemented what he saw as exciting from those movies into gameplay.
With utter disregard for copyright law, he said, he took those frames, did his animation implementation technique, and put it into the game. And that fight scene from Robin Hood mimics exactly what is found in the original game.
His New Year's resolution in 1989 was simply to finish the game. He took cues from Mario and other favorite platforming games. In May, he was still tweaking game design, trying to create special moments without creating new assets. His dad composed the music, which was limited by the Apple II's abilities.
The final bit of the game involved creating the boss fight with Shadowman. He said that due to time and memory constraints, that paradoxical boss fight was quite simple, and it came about in less than a day.
The game emerged on the Apple II in October 1989, and the sales were pathetic, he said. There was still some hold for the PC and Amiga versions, which launched in May 1990 with remastered audio and improved graphics, but these versions also flopped. The reason for this was that it was a conversion, and retailers didn't want to sell it. By September, it had been delisted due to a lack of sales. The game had sold 10,000 copies across all formats at that point, and it looked like that would be it.
However, they were saved by the Mac version, a new marketing department, a new box, and foreign licensing. By the time it came out for the Mac in May 1992 there was a market. The game went on to sell 2 million copies worldwide.
Quote: "These technical difficulties are going to pale to what I'm about to describe to you from what happened in 1985."--Jordan Mechner, after 15 minutes of wrestling with his A/V equipment.
Takeaway: Prince of Persia went through a good deal of iteration and conceptual retooling before turning into the multimillion-unit hit that it eventually became. However, through it all, the core idea of fluidity in animation remained the same, even if the puzzle-platforming adventure game elements saw dramatic changes.
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