What is Costume Quest Decompilation?

Costume Quest Decompilation is an open-source decompilation of Costume Quest. Source code reconstructed from the original game's compiled binary, so the game can be understood, rebuilt and ported.

Do I need the original game files to run Costume Quest Decompilation?

Yes. The project does not include the original game's assets, so you need your own copy.

Costume Quest Decompilation

DecompilationHalted

Source code reconstructed from the original game's compiled binary, so the game can be understood, rebuilt and ported.

Based on Costume Quest

Image of the original game, Costume Quest. This project has no screenshots of its own yet.

Costume Quest (original game, not this project) — Image of the original game, Costume Quest. This project has no screenshots of its own yet.

Links, repository & details

About

A decompilation of the Steam release of Costume Quest. The author says progress will likely be slow because it is a one-person project, and the goal is full, functionally matching source code. It takes a hooking approach: a DLL is patched into the game's import table and gradually replaces more of the game's functions.

Getting started

You need the Costume Quest game files in a costume_quest folder, the Steamworks SDK version 1.14 in its own folder, and Ultimate-ASI-Loader's dinput8.dll alongside. The official executable is launched and the decompiled DLL is injected into it. It builds with CMake for Visual Studio 2022 (Win32).

What you need to run it

Original game files required. The project ships code only; you provide your own copy of the game.

The game's files must be in `project_root/costume_quest`.
Ultimate-ASI-Loader's `dinput8.dll` must be in the same folder.

How to install

Place the game files in `project_root/costume_quest`.
Place Ultimate-ASI-Loader's `dinput8.dll` in the same folder.

Summarised from the project's README.

Additional notes

Engine: The README states that Double Fine Productions used their in-house engine Buddha for Costume Quest.

FAQ

What is Costume Quest Decompilation?: Costume Quest Decompilation is an open-source decompilation of Costume Quest. Source code reconstructed from the original game's compiled binary, so the game can be understood, rebuilt and ported.
Do I need the original game files to run Costume Quest Decompilation?: Yes. The project does not include the original game's assets, so you need your own copy.