Phaethon

Combat Racing

Jak X

Combat racing across the trilogy's world, which OpenGOAL never ported.

Get Phaethon The four cores
Where it stands

Runs start to finish on this fork, the credits included; the online layer is on the roadmap.

counted in the tree at develop 32de6fb on Oct 17, 2026 · a line is one of GOAL code, not a blank or a comment · a definition is one of the game's functions, methods, states or types

677,957lines of GOALfrom 68,262 when the fork began
12,665definitionsfrom 2,010
575states, each a thing an object can be doingfrom none
469models with their animationsfrom 3

Status

Playable

Released

2005

Discs

SCUS-97429 (NTSC-U)

Source files

780 in the tree at develop 6332c399

The game

Poisoned, with the antidote as the prize.

A year after the trilogy, Jak and his friends are poisoned at the reading of a will in Kras City, and the antidote goes to whoever wins the city's combat racing championship. So they race, through Kras City, the trilogy's old ground and its arenas, picking up eco weapons on the track to fire at the other drivers or to fend them off.

It was the series' first game with multiplayer, online included, over a service long since shut down. Its driving was built on Jak 3's, and save data from the earlier games unlocks extra drivers, among them Ratchet from Insomniac's Ratchet and Clank.

Developer
Naughty Dog
Publisher
Sony Computer Entertainment
Released
October 2005
Genre
Combat racing
Jak X: Combat Racing's title menu, the game's logo over a racer in its garage, with Adventure, Exhibition, Customize, Profile, Options and Secrets Shop
After the bones

Upstream left the bones. The rest was built here.

OpenGOAL never brought Jak X up. When Phaethon forked in July 2026, upstream's tree held only its bones: 208 files with code, 127 of them type headers, beside the kernel, math and file loading. The main loop, the levels, the menus, the races and the network code were empty files, and asked to run Jak X the program answered that the game was not supported.

Every file after that landed through this fork. Jak X grew from 2,010 definitions to 12,665, from no states to 575 and from three art groups to 469; counted in tokens, the one measure a formatter cannot move, it is now about the size of Jak II. Its bring-up milestone closed on October 1st with 636 issues, and on October 9th a playtester's run reached the credits.

  1. 01

    Boot

    Run the game until it stops.

  2. 02

    Read the stop

    Find what it reached for that was not there yet: a function, a type, a level.

  3. 03

    Decode

    Take that object from the disc and translate it into GOAL, typed and checked.

  4. 04

    Land

    Merge it through the same gates as every change, then boot again.

  1. PS2Jak X: Combat Racing ships, with online play.
  2. OpenGOALThe first Jak X kernel work is proposed upstream.
  3. OpenGOALUnfinished Jak X work from several contributors is gathered into one change so it is not lost.
  4. PhaethonThe kernel's dispatcher runs, and a Jak X process is alive for the first time.
  5. Phaethonbrdroom loads, the first level with real geometry.
  6. PhaethonThe main menu draws with its real six entries.
  7. PhaethonThe network code runs, over a loopback on one machine.
  8. PhaethonThe first full lap. Until then a race died at its first crossing of the line.
  9. PhaethonThe first full race against computer drivers, through to the results.
  10. PhaethonThe bring-up milestone closes with 636 issues.
  11. PhaethonThe boss battle lands, and a win reaches the gold medal and the credits.
  12. PhaethonThe credits roll, after two crashes in Kleiver's cloth.
Phaethon

Built with AI in the loop. Phaethon uses AI assistance for speed and accuracy, and holds it to the same bar as every other contribution: every change is read, tested and checked against the console before it lands.

Project

About FAQ Docs

Cores

Jak and Daxter Jak II Jak 3 Jak X: Combat Racing

Play

Download the launcher Import a disc System requirements Your account

Community

Report a bug Contact
develop 6332c399 CI green v0.2.1 Nov 4, 2026

Phaethon is an unofficial fan project. It is not affiliated with, endorsed by or associated with Sony Interactive Entertainment, Naughty Dog or the OpenGOAL project. Jak and Daxter is a trademark of Sony Interactive Entertainment. You need your own copy of each game. Icons from Lucide, ISC; JetBrains Mono under the SIL Open Font License.

Under construction

This site is still being built.

Nothing links to playphaethon.com yet, so you have found it before it is ready. Some of what it says may be wrong, out of date or attributed to the wrong source. Treat it as a work in progress until this notice is gone.