Cryptmorrow ZX
The dungeon explorer of Cryptmorrow for the ZX Spectrum. Sixteen rooms beneath the hill of Morrow, keys and locked doors, skeletons and bats, three seals and the portal of the Moss Gate, with AY music on the 128K.
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ZX Spectrum Game Manual Series · Volume 1
Cryptmorrow ZX
Z80 Assembly: Build a Complete Dungeon Explorer for the ZX Spectrum
Build a full game
Build a complete ZX Spectrum game in Z80 assembly, one playable step at a time
Under the hill of Morrow lies a crypt of sixteen rooms. Torches burn in halls green with moss, skeletons still guard the corridors, bats wait in the dark, and three seals open the portal of the Moss Gate. Cryptmorrow ZX is the dungeon explorer of the Commodore 64 book, written again for the ZX Spectrum: its Z80, its screen of colour attributes, its beeper and the AY chip of the 128K. This book shows you how to build it yourself, from the first room on the screen to the finished tape with its title, its music and its endings.
The complete game is yours. The companion repository holds the full source code under the MIT licence: the finished game, the eight steps of the book, 22 ready-made experiments, the tests and the tools. The game is also there ready to play, as a tape image that runs on the 48K and the 128K.
All you need is three free programs: the sjasmplus assembler, the Fuse emulator and Python. Every listing in the book is real code of the game, and every picture is a real screen of the program.
Cryptmorrow ZX is the first volume of the ZX Spectrum Game Manual Series, where every book is independent and brings a new original game to life. Load the tape, light the first torch and step under the Moss Gate.
Inside the book
- Sixteen rooms beneath the hill of Morrow, seen from above: an atrium of seven rooms and three zones of three, drawn from tiles
- An explorer drawn as a software sprite, who walks, stops at walls and fights with a blade
- Keys and locked doors, treasures and potions, and three seals that open the portal of the Moss Gate
- Skeletons that patrol and bats that give chase, with blows, damage and GAME OVER
- Music on the AY chip of the 128K, effects on the beeper of every Spectrum, and a MUSIC, SOUND FX or SILENT menu
- A title in big letters, Kempston, Sinclair or keyboard controls, victory and defeat screens
- A tape with a BASIC line, a loading screen and the code, loaded through the ROM as a Spectrum loads it
What makes this book different
No assembly experience needed
The book starts from the Z80, its memory and its screen, before the first line of the game.
Eight playable steps
From the first room to the finished tape. Each step is a complete program, and its size and SHA-256 fingerprint tell you that you built exactly the program in the book.
Make it yours, then break it
14 guided experiments change speeds, colours, damage, music and names; 8 “Where it breaks” versions make the classic mistakes on purpose and explain them.
Tested frame by frame
The tests load the tape through the ROM in a simulator and compare every frame of play with a model of the game, the screen byte for byte, the AY and the beeper too.
The game in this book
The game you build
Contents
17 chapters
Seventeen chapters, eight steps
01Your workshop
02The Z80, memory and the screen
03The tile engine
04Text, torches and the frame
05Software sprites
06The explorer
07The dungeon and the HUD
08Objects, doors and the portal
09The enemies
10The blade and the damage
11The AY and the music
12The beeper, the effects and the sound modes
13The title and its big letters
14States, menu and end screens
15The tape
16Reading and checking the game
- 17Glossary and index
Errata
Corrections
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.