Cpp2IL

Cpp2IL is a work-in-progress tool that reverses Unity's IL2CPP build process, recovering managed DLLs from a compiled game's native binary and its metadata. It is written in C# and distributed as a command-line application plus a "core" library (published on NuGet as Samboy063.Cpp2IL.Core). It uses the bundled LibCpp2IL library, MIT-licensed, to parse IL2CPP metadata structures.

The current development branch is a major rewrite. The CLI is organised around output formats (selected with --output-as) and processing layers (--use-processor), replacing many earlier options. Analysis is off by default and can be enabled with the dll_il_recovery output format. Analysis uses an intermediate representation called ISIL and a control flow graph. Mono.Cecil has been replaced by AsmResolver.DotNet, and a plugin system is planned for custom instruction sets and binary formats.

It can be pointed at a Windows game folder or, in recent versions, at a single APK file, and it detects the Unity version and locates the files it needs. The README says the recovered CIL is often messy and recommends ILSpy for viewing it. Some formats and layers are not yet implemented, so functionality is limited compared with earlier releases. A YouTube creator mentioned it as a tool for decompiling Unity games that AI agents can use for reverse engineering.