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

v1.0.0-beta2

Run & debug

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

The Bizmuth emulator →

FantASM

v2.0.0

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 →

Sep 4, 2026

FantASM

FantASM 2.0.0 is available

FantASM 2.0.0 is available to download. The editor now answers with what the build answers. Libraries get a real interface, tests get spans and checksums, and 5…

Sep 2, 2026

Bizmuth beta

Bizmuth 1.0.0-beta2 is available

Bizmuth 1.0.0-beta2 is available to download — 174 changes since beta 1. Mostly correctness: 123 fixes, a lot of them hardware behaviour that had been quietly w…

Aug 23, 2026

Bizmuth beta

Bizmuth 1.0.0-beta1 is available

Bizmuth 1.0.0-beta1 is available to download — the first beta of the 1.0 line, and the release where Bizmuth starts running on hg80, our own Z80 and Z80N CPU co…

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