SHADOW MAN. Credit Tomi with this one.
I was explaining to her why there are no enemies in Prince of Persia. The animations for the player’s character are so elaborate, there’s not enough memory left to add another character.
“Why not use the same animations for your enemies, the way you did in Karateka?”
“Wouldn’t work so well this time. This character is designed to look cute. He has a very specific personality in the way he runs and moves. The enemies would have to be cute too.”
“Can’t you just change the face, or the costume?”
“Not possible. If I change anything, it’s a whole new set of shapes. There’s just no memory.”
She wouldn’t give up. “Couldn’t you make him a different color – say, black?”
I started to explain: “This is the Apple II…” and then it hit me: What if I exclusive-OR each frame with itself, bit-shifted one pixel over? I visualized a ghostly, shimmering outline-figure, black, with white face and arms, running and leaping, pursuing you. I described it to Tomi.
“Shadow Man!” she exclaimed.
Tomi, Robert, and Eric all huddled around my screen while I paged through my source code.
Me: “Uh, you don’t actually have to watch me do this. It might take a while.”
Eric: “No, we want to. It’s a test.”
In about two minutes I had Shadow Man up and running. He looked great. It was as if he’d always existed. Everybody was wowed. How could I have ever contemplated the game without him?
Robert suggested that Shadow Man could come into being when you run through a mirror. You leap through the mirror; simultaneously your evil shadow self leaps out the way you came, and slinks off into the darkness. For the rest of the game he’s lurking in the shadows, dogging your steps… until the end, when you don the magic amulet and become powerful enough to reabsorb him into yourself, thus gaining the strength you need to defeat the Grand Vizier.
“You’ll sell a billion copies,” Tomi predicted. “All I want is a Honda Legend. Coupe. Silver.”