Reconstruction of ZZT

About

ZZT is a 1991 action-adventure puzzle game and game creation system by Tim Sweeney for MS-DOS, notable for its built-in editor and its own scripting language, ZZT-OOP, that let players build and share their own worlds. The Reconstruction of ZZT is a reverse-engineered recreation of the source code for ZZT 3.2, the last official release; the compiled output is byte-for-byte identical to that release. Because ZZT's original source code was lost, the project rebuilt it through careful reverse engineering, a process the author documented in a blog article.

Getting started

Building requires a DOS environment (e.g. DOSBox) and Turbo Pascal 5.5 via the included BUILD.BAT script; a Free Pascal build is also possible with some code modifications, though the resulting binary is about 40KB larger. To create ZZT worlds, use the built-in editor (press E) or a community tool like KevEdit.

What you need to run it

Features

• The executable matches the original release byte for byte and represents its engine behavior.
• The binary distribution includes the ZZT engine, documentation, a demonstration world, and a configuration file set to open that world by default.

Controls

• Press E to open the built-in editor.

Licensing & legal

• The bundled LZEXE compressor was confirmed in May 2025 to also have MIT-licensed source code.

FAQ

What is Reconstruction of ZZT?

Reconstruction of ZZT is an open-source decompilation of ZZT. Source code reconstructed from the original game's compiled binary, so the game can be understood, rebuilt and ported. The original game ran on DOS.

Do I need the original game files to run Reconstruction of ZZT?

According to the project's README, no original game files are required.

How is Reconstruction of ZZT licensed?

project: MIT (source code release, excluding the listed files); Fabrice Bellard: FREEWARE (TOOLS/LZEXE.DOC and TOOLS/LZEXE.EXE); Adrian Siekierka: zero-clause BSD (MISC/relocfix.py). The repository itself is the authoritative source.