Atari 2600 Game Manual Series · Volume 1
6502 Assembly: Build a Complete Dungeon Adventure for the Atari 2600
Build a full game
Scalecrown is the first volume of the Atari 2600 Game Manual Series, where every book is independent and brings a new original game to life.
Beneath the ruins of Oakhaven lies the Crypt of Scales, and in its depths the Scalecrown, a relic of dark magic that bends every reptile in the land to its will. Sir Roderick, a wandering knight with a steel sword and an oak shield, goes down to destroy it before the curse smothers the kingdom. On the throne, the Serpent King is waiting.
The game is sixteen rooms on four levels, each narrower and more dangerous than the last: spikes that rise and fall in the floor, a key in a chest on every level and the door it opens, serpents that give chase and come back, and in the throne room the Serpent King, whose venom only the shield can stop. Break the crown, and the curse breaks with it.
The book builds the game in nine playable steps, from the first room to the finished cartridge, with 27 experiments along the way: 18 guided changes and 9 “Where it breaks” versions that make a classic mistake on purpose. The complete source code, every step and the cartridges for NTSC and PAL televisions are free on GitHub under the MIT licence, and every listing in the book is part of a file there, line for line.
Story and characters by Rohan A. Banerjee.
What makes this book different
Eight banks of 4K and the 128 extra bytes of RAM of the Superchip (F4SC). The book shows why the game needs them, and how every bank finds the others.
Living stone and light that change line by line, a knight drawn at full resolution, torches and water that move, and flicker only where two objects share the same lines.
The room kernel is measured line by line, down to the line with a single free cycle, and the book shows where each of the 76 cycles of a scanline goes.
The same seconds and the same pictures on both televisions, checked by tests that play the cartridge in a simulator and in Stella, starting from every one of its eight banks.
The game in this book
Sir Roderick goes down into the Crypt of Scales to destroy a cursed crown: sixteen rooms on four levels, timed traps, keys and doors, serpents that give chase, and the Serpent King on the throne. A 32K cartridge for the Atari 2600 in 6502 assembly.
From Scalecrown
Contents
Errata
No errors have been reported for this edition yet.
Found a mistake? Open an issue on GitHub or write to [email protected], with the page number and what it should say.
