Writing a Demoscene Intro for the ZX Spectrum

A developer rebuilt a classic demoscene "crack intro" for a stock 128KB ZX Spectrum, deliberately packing late‑80s tropes - a smooth scroller with custom "leet" fonts, a three‑channel AY soundtrack, bouncing VU meters and a parallax starfield - into a compact program (10,287 bytes of code; 19,552 bytes as a .tap). The project is rooted in nostalgia for Amiga cracktros and the evolution of the demoscene, and reproduces the visual and audio conventions of those early single‑screen productions while offering ready‑to‑run downloads, a YouTube capture, pouet.net listing and TNFS hosting for real hardware testing.

Technically, the build used a Makefile pipeline with the Pasmo assembler, a fork of zmakebas, and the FUSE emulator, plus a TNFS server to load .tap images on a +3. The author relearned Z80 assembly using a web asm‑editor to step through instructions and relied heavily on pen‑and‑paper mapping of bytes, attributes and register state (and canine "rubber‑duck" debugging). The writeup shows specifics: SCREEN$ dumps loaded at 16384 (0x4000), a 6912‑byte screen memory layout, and example code (org $8000, screen equ $4000, scrlen equ 6912, out (ula) to set border), plus practical tricks and frustrations encountered while squeezing effects into tight memory and timing constraints.