Alpha build 2026.10.15

Alpha build 2026.10.15

This update replaces the ZT1 Lab installer with a build that includes the previously missing standalone behavior and shared knowledge base connection.

• The Lab uses the bundled ZT1 Engine when a selected source checkout has no engine build of its own.
• The installer offers a standalone mode that does not require selecting a repository checkout.
• The Lab includes the public shared knowledge base endpoint, so users can pull and contribute without configuring a URL. Findings remain provisional until reviewed, and contributions are checked against the supported 2002 Complete Collection build.
• The Lab package includes the Ghidra startup and Steps panel fixes.

The ZT1 Engine installer and game build remain at 2026.10.14 in this release. The game updater feed and their original assets are carried forward unchanged. The Lab installer contains the author's engine and third-party components only; Zoo Tycoon game files and private game data are not included.

Alpha build 2026.10.14

Fixes the game updater's false and unsigned update offers. The engine now accepts only a signed release feed and checks the downloaded installer against its signed size and SHA-512.

Fixes ZT1 Lab's Ghidra setup on a clean machine. The Lab now starts its bundled Ghidra bridge itself and builds a project from the player's installed zoo.exe when needed, with progress shown in the app.

Also fixes the Original Game Steps window resizing inside the Lab and centers the game's main menu button text correctly.

Alpha build 2026.10.13

Alpha build 2026.10.13

A new alpha with real additions. You still need your own copy of Zoo Tycoon — this ships none of the game's files and plays the copy you have installed.

What's new

• Updates. The installed engine now offers each new alpha at the main menu: Update now, Later, or Skip this version. Your saves, mods and settings are kept.
• Game Options work. The original's Sound, Video, Tooltips and Scrolling settings now do what they say, and are remembered.
• An Extras tab in Game Options switches each of the engine's additions on or off. Switched off, it plays exactly as the original.
• Building placement fixed. Buildings snap to whole tiles, as in the original.
• Money as the original counts it. An animal's sale price and the admission price follow the original's rules.
• Marine Mania animals (needs the Complete Collection):
  • Build tanks and adopt marine animals.
  • Put a filter beside each tank: it goes on the tile you click.
  • Marine Specialists work inside the tank, as in the original. They climb in at the gate and dive. Underwater they feed the animals, rake dung, heal and sweep murky water, then climb back out.
  • Maintenance workers repair worn filters.

Still to come: Marine Mania's animal shows (a later alpha), Dinosaur Digs (not ready), scenario goals and events, and loading the original game's .zoo saves.

What to download

Two of these play the game. The third is a tool for looking inside it.

File	What it is
ZT1-Engine-Setup-2026.10.13.exe — 4 MB	The engine. Get this one. An installer with no admin prompt. It reads your Zoo Tycoon where it's installed, and offers each new alpha at the main menu.
ZT1-Game-Build-2026.10.13-win64.zip — 3 MB	The other way to play. A folder that runs on its own, like the first alpha: unzip it anywhere and run start.bat. The first time, it copies your Zoo Tycoon's files in beside the engine — for that it needs Python 3. After that the folder plays by itself, but it doesn't update itself: download the next one when it's out.
ZT1-Lab-Setup-2026.10.13.exe — 570 MB	Not needed to play. The workbench this engine is developed with: it reads your own zoo.exe, shows what each address in it does, records which code runs in which situation, and edits and builds the engine's code. Released beside the game for the first time. Skip it unless that's your thing — details below.

Every download has its .sha256 beside it, so you can check what you got.

The ZT1 Lab, if you want it

It installs the same way, for you alone with no admin prompt, from the Start menu as ZT1 Lab. Everything it needs is inside it — the decompiler (Ghidra) and the Java it runs on, an embeddable Python with the packages its tools use, and its knowledge base — so there is nothing to install first. It reads Zoo Tycoon where it already is, and like the engine it ships none of the game's files.

You can point it at the engine's source if you have it (it will ask), or let it use what it carries.

If Windows warns you

The installers aren't signed yet, so Windows doesn't know them. Click More info, then Run anyway.

Found a bug?

Report it at https://github.com/AlexC1991/zt1-engine/issues. The most useful report says what you did, what the original game does, and what the engine did instead.

Alpha build 2026-10-09

Re-packed 2026-10-12: the download no longer includes copies of Zoo Tycoon's own files (they were in pc-sync/). Nothing changes for players: the engine always read them from your own install.

ZT1-Engine — Alpha Build (2026-10-09)

An open-source engine for Zoo Tycoon 1, for 64-bit Windows.

⚠️ This is a taste of what's being made, not a finished game

This alpha is an early look at work in progress. Please don't judge it as a finished product, and especially not by how much is available right now. A lot is missing, some things are rough, and some things will break. It's here so you can try it, see where it's heading, and help by reporting bugs.

Back up any saves you care about.

📅 New alpha every week

A new alpha build will be released every week. Each one brings fixes and more of the game. Check back for the latest.

You need your own copy of Zoo Tycoon. This download has the engine only, with no Zoo Tycoon art, sound, maps or game files. The first time you run it, it imports them from your own install.

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Which Zoo Tycoon do I need?

The base Zoo Tycoon game is all you need. You do not need the Complete Collection.

• Base Zoo Tycoon only: works. This alpha is built around the base game, and everything that's ready uses only base-game content. (Tested with just the base game: setup and play work.)
• Complete Collection (with Dinosaur Digs and Marine Mania): also works, and setup imports the expansion files too. But expansion content isn't ready in this alpha (see below), so you don't gain much from it yet.

If you only have the base game, setup shows a warning that Dinosaur Digs and Marine Mania content is missing. That's expected and safe to ignore.

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Requirements

Windows	10 or 11, 64-bit
Zoo Tycoon 1	The base game is enough (installed or extracted). The Complete Collection works too, but isn't needed
Python 3	Used once, to import your game files. python.org/downloads. Tick "Add python.exe to PATH" when you install it
Visual C++ Redistributable 2015–2022 (x64)	Most PCs already have it. If you get an error about MSVCP140.dll or VCRUNTIME140.dll, install it from aka.ms/vs/17/release/vc_redist.x64.exe
Disk space	About 0.5 GB after setup with the base game, about 1.1 GB with the Complete Collection (the imported game files)

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Installing and playing

1. Unzip the folder anywhere you like, such as your Desktop or Documents. Avoid Program Files, because Windows blocks writing there.
2. Double-click start.bat.
3. First run only: it checks the usual install folders (Program Files (x86)\Microsoft Games\Zoo Tycoon and similar). If your game isn't in one of them, a window asks you to pick the folder that contains animals.ztd and zoo.exe. The folder is remembered.
4. It imports the game files and sets everything up (about a minute), then the game starts.

After the first run, double-click start.bat again to play. You can also run the game directly with
build\Release\zt1-engine.exe. If you make a shortcut to it, keep "Start in" set to that build\Release folder.

Where your files go

• Saved zoos: Documents\zt1-engine\Saved Games
• Snapshots: Documents\zt1-engine\screenshots

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What you can try in this alpha

This alpha covers the base Zoo Tycoon game's freeform mode: its animals and items. If you find a bug in any of it, please report it (see Reporting bugs).

• Menus: loading screen, main menu, freeform map selection, credits, the in-game HUD, panels, tooltips and messages
• Base-game animals: adopting and selling, eating, drinking, sleeping, swimming, happiness and exhibit suitability, breeding, illness and old age
• Base-game items: terraforming (raise, lower, smooth, paint), paths, fences and gates, exhibits, scenery, foliage, rocks, shelters and toys, the bulldozer and undo
• Escapes and predators: animals jump, climb or break out; loose meat-eaters chase guests, and keepers dart and crate them
• Guests: needs, tours, donations, thoughts, litter, and running from escaped animals
• Staff: zookeepers, maintenance workers and tour guides; hiring, firing and duties
• Running the zoo: zoo rating, admissions, finances, graphs, research and conservation
• Saving and loading: Save Game, Load Game and Continue Saved Game
• Sound: music, ambience, crowds, guests and animals

Camera: arrow keys or W A S D move · [ / ] zoom · Q / E rotate the view.

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Known bugs and what's not ready

🐞 Buildings: placement is broken (known bug)

Buildings (shops, restaurants, restrooms and other guest buildings) are in the game, but placing them is broken in this alpha. They may go in the wrong spot or not place properly, and the behaviour isn't the same from one PC to another. It's a known bug being worked on, so you don't need to report it. Please avoid relying on buildings for now. A fix is planned for an upcoming weekly build.

Not in this alpha yet

• Dinosaur Digs and Marine Mania: expansion animals, tanks, shows and dinosaurs are still being built. Their content may show up in menus and buy panels, but it isn't ready to play.
• Scenarios: they open, but their goals and events aren't implemented yet. Stick to freeform.
• Original .zoo saves: can't be loaded yet. The engine uses its own save format, so saves from the original game won't open.
• Linux and macOS: Windows only for now; other platforms are planned.

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Troubleshooting

"Python was not found"
Install Python 3 from python.org, tick "Add python.exe to PATH", then run start.bat again.

MSVCP140.dll or VCRUNTIME140.dll is missing
Install the Visual C++ Redistributable (x64).

Setup warns that Dinosaur Digs / Marine Mania content is missing
That's normal if you only have the base game. Ignore it; this alpha doesn't need the expansions.

It used the wrong Zoo Tycoon folder, or I want to import from a different one
The files are only imported once, so start again from scratch. Open a Command Prompt in the unzipped folder and run:

start.bat --clean
set ZT1_SOURCE_DIR=D:\Games\Zoo Tycoon
start.bat

Replace the path with the folder that has animals.ztd and zoo.exe in it.

Sound is slow, scratchy or muffled
The engine uses DirectSound by default, because Windows' newer WASAPI audio sounded wrong on some PCs. To try a different audio driver, open a Command Prompt in the build\Release folder and run:

set SDL_AUDIODRIVER=wasapi
zt1-engine.exe

This only affects that one launch. It doesn't change anything else on your PC.

Something went wrong during setup
Run start.bat --clean, then start.bat again for a fresh setup. --clean removes the imported game files (they're imported again on the next run) but keeps the engine. Your saved zoos in Documents are not touched.

start.bat options

Command	What it does
start.bat	Set up (first time) and play
start.bat --setup	Only import the game files, then stop
start.bat --clean	Remove the imported game files and settings for a fresh setup (keeps the engine)

To import from a particular folder, set ZT1_SOURCE_DIR=<folder> before running start.bat.

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Reporting bugs

This alpha exists to find problems, so if you find a bug, please report it. Every report helps the weekly builds get better. The most useful report shows where the engine differs from the original game:

1. What you did
2. What the original Zoo Tycoon does
3. What the engine did instead

Add a screenshot or your saved zoo (from Documents\zt1-engine\Saved Games) if you can. Saying which alpha build (the date in the folder name) you were playing helps too.

Report issues at https://github.com/AlexC1991/zt1-engine/issues.

Building placement is already known (see Known bugs), so there's no need to report it.

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Legal and credits

Zoo Tycoon is © Microsoft Corporation, developed by Blue Fang Games. This project is not affiliated with or endorsed by Microsoft or Blue Fang Games. It ships none of the original game's files. You need your own legitimately obtained copy.

ZT1-Engine is free and open source under the MIT License (see LICENSE.txt), © 2025 Wouter (sharkwouter) Wijsman and contributors.
Source code: https://github.com/AlexC1991/zt1-engine

It uses these open-source libraries: SDL2, SDL2_image, SDL2_mixer, SDL2_ttf, FreeType, libzip, zlib and pe-resource-loader. Portions of this software are copyright © The FreeType Project (www.freetype.org). All rights reserved.

The icon uses a photo by Magda Ehlers from Pexels.

This software is provided "as is", without warranty of any kind. It's an alpha: use it at your own risk.