Homebrew tools for retro development

TwistedRaven is one person building the retro-development tools I always wished I had — an assembler, a language and an emulator, made for the fun of it.

Bizmuth

v0.9.5-beta5

Run & debug

A ZX Spectrum Next emulator with a source-level debugger, breakpoints and scripting.

The Bizmuth emulator →

FantASM

v1.8.0

Assemble

A cross-platform Z80 assembler — the complete Z80 and Z80N instruction set, macros, structs and Rhai scripting — with first-class ZX Spectrum Next support.

The FantASM assembler →

Zinc

In development

Write

A modern, Rust-flavoured language that compiles straight to Z80 — high-level ergonomics, no runtime overhead.

The Zinc language →

Other tools

0x1DE

Extension

The VS Code / VSCodium extension — FantASM language support and Bizmuth source-level debugging in your editor.

Get 0x1DE →

Rookery

macOS

A macOS menu-bar host for a Gitea act_runner — keeps a self-hosted CI runner connected.

About Rookery →

Latest news

All news →

Aug 19, 2026

FantASM

FantASM 1.8.0 is available

FantASM 1.8.0 is available to download. It’s a big one: modules grow up, the !test simulator changes CPU, and there are four breaking changes — read those first…

Aug 18, 2026 hg80

Introducing hg80

hg80 (“Mercury”) is the CPU at the bottom of the toolchain — a Z80 and Z80N core, stepped one clock edge at a time. It’s the processor Bizmuth will run on, and …

Jul 28, 2026

Bizmuth

Bizmuth 0.9.5-beta5 is available

Bizmuth 0.9.5-beta5 is available to download.

Early days yet — three tools so far, and more whenever the itch strikes.