What you need

You need your own disc or disc image of each Jak game you want to play. The port reads its files from a disc dump; it does not ship or download any of them for you.

Before it starts extracting, the launcher reads the disc image's PlayStation 2 system file and checks the serial against what it knows, so a Jak II disc on the Jak 3 tile gets caught before it wastes your time on a bad extraction:

Game	Known disc serials
Jak and Daxter	SCUS-97124 (NTSC-U, Black Label and the later print), SCES-50361 (PAL), SCPS-15021 (NTSC-J), SCPS-56003 (NTSC-U)
Jak II	SCUS-97265 (NTSC-U), SCES-51608 (PAL), SCPS-15057 (NTSC-J), SCKA-20010 (NTSC-K)
Jak 3	SCUS-97330 and SCUS-97516 (NTSC-U, including the Greatest Hits print), SCES-52460 (PAL), SCKA-20040 (NTSC-K)
Jak X: Combat Racing	SCUS-97429, SCES-53286

A serial that is not on this list is not refused outright: the launcher hands it to the extractor's own database rather than guessing at it.

The launcher itself is a Windows desktop application, so the launcher road needs Windows. The port renders through Vulkan by default, with the OpenGL backend kept. The remastered preset's upscalers need matching hardware: DLSS needs an NVIDIA GPU, and FSR runs through AMD's FSR 3.1.

Installing and importing your disc

1. Install the launcher. It ships as a single self-contained executable.
2. The first run opens a short setup wizard: where the runtime and every game's data should live (one folder for all four games, C:\Jak by default, each game's data kept apart underneath it), how thoroughly update checks should verify what is already on disk (hashing every file, or a quicker check you can escalate to a full one later), and a few extras like Discord presence and automatic updates. You can install the runtime right from the wizard or finish it and explore first.
3. Open a game's page and point its disc field at your disc image. Starting the import runs the fork's extractor through three stages you can watch progress on: extract, decompile, compile.
4. Once it succeeds, the launcher records when the import happened, and the game's card in your library reads ready to play.

Everything the import produces lands under the install folder's data subdirectory: the extracted disc under iso_data\<game>, the compiled build under out\<game>\iso. The launcher's own settings, its per-game records (disc path, preset, extra launch arguments, enabled modes) and its logs live separately, under %AppData%\JakLauncher.

First launch

Play starts gk.exe with --game <name>, your project folder as --proj-path, and the standard -boot -fakeiso pair, adding -debug and any extra arguments you set per game. Every game starts retail-faithful; the enhancements are individual toggles in the game's options and the launcher, covered on Settings and the remastered toggles.

Building from source instead

If you would rather compile the game yourself from a checkout of this repository, the toolchain, the task commands and the REPL road are on Building from source.

When something goes wrong

Start on Reporting a retail divergence if what you are seeing is the port behaving differently from the PlayStation 2 original; that form asks what retail does and how you know, which is what makes a report useful. For a crash or a hang, the game's log sits under %APPDATA%\Phaethon\<game>\log\; attach the newest one, and the crash block too if the game printed one. Anything else goes through the issue forms, which cover general bugs, performance and feature requests as well.

Phaethon is a hard fork of OpenGOAL's jak-project. Naughty Dog made the games; you need your own copy of each. built from the wiki · 27 Sep 2026