It reads the data.win file (or equivalent bytecode files on Mac, Linux, and Android) and completely disassembles it.

Competitors can rip unique algorithms or systems you spent months building.

is arguably the most complete and well-known tool for modding, decompiling, and unpacking GameMaker games. It's an open-source project that has been in active development for years, capable of reading a vast array of GameMaker versions, including GM:S 1.4 and GMS2 (supporting bytecode versions 13 to 17 as of late 2023). While incredibly powerful for viewing and editing compiled game data, its primary interface is built for modders, and its output isn't a clean project file.

A GameMaker Studio 2 decompiler is a dual-use technology. In the hands of a developer recovering lost work or a community creating localizations, it is an invaluable tool for preservation and creativity. In the hands of bad actors looking to clone or pirate software, it poses a security threat. By understanding how GMS2 compiles data and utilizing the YoYo Compiler, developers can successfully safeguard their creative investments while respecting the technical curiosity of the broader engineering community.

In the security world, reverse engineering is a standard practice. Security researchers may decompile a GameMaker executable to confirm a false-positive detection (where an antivirus mistakenly flags a benign game as malware) or to analyze a real threat. This is a specialized use case that typically uses professional tools like Ghidra or IDA Pro , not the modding-focused tools discussed here.

Several community tools have attempted GMS2 decompilation:

file back into its original assets and source code. While technically complex, several community-developed tools can assist in retrieving scripts, sprites, and room data, especially for games compiled using the Virtual Machine (VM) 1. Understanding GMS2 Compilation Targets

However, the legal situation isn't uniformly prohibitive. Some argue that "decompilers are not illegal. It's just a particular way to do reverse-engineering". The primary restriction comes from EULAs you agree to when using GameMaker. As one community member notes, "The only way you could be not allowed to do it is if you signed a EULA saying you will never reverse-engineer or decompile the software in question".

However, because the default VM export leaves your hard work completely exposed, you should always compile your commercial releases using the to keep your code and assets secure.

Hardware failures, corrupted hard drives, and accidental deletions happen. If a developer loses their original GMS2 project files but still has a compiled VM build of their game, a decompiler can save hundreds of hours of work by recovering the source code and assets. 2. Modding and Localization

A is a tool designed to take a compiled GameMaker game executable and extract its original assets, sprites, audio, and, most importantly, its GameMaker Language (GML) code.