Canon Discontinuity: For Epic themselves and many people, Unreal Tournament 2003 never existed, and said game is a beta version of Unreal Tournament 2004 instead. It gets weird storyline-wise, since the events of that game (most notably Gorge being the current Champion) still technically happened.
Unreal Championship was also erased from the timeline.
Official Fan-Submitted Content: Most of the content of the Bonus Pack 2 is composed by entries of the "Make Something Unreal Contest". CTF-CBP2-Pistola won the Best Map award, while all of the Assault maps except AS-BP2-SubRosa were placed between 1º and 5º places in the Best Assault Map category.
Updated Re-release: It should be noted that all of the upgrades and features available in the updated releases are also available as free downloads to owners of the original game. 2004' serves as a notable exception, where instead owners of 2003 were able to receive a discount on their purchase of the game.
Unreal Tournament 2004 towards Unreal Tournament 2003: UT2003 + its two Bonus Packs + extra content.
2004 itself has the Editor's Choice Edition, which included several mods and the Editor's Choice Edition Bonus Pack, which was later released as another free Bonus Pack.
Championship had a lot of broken promises, such as massive multiplayer battles which involved giant maps and up to 64 players.
Vehicles were set to appear as far asChampionship.
The HUD messages for the Championship betas were taken almost verbatim from those of Tournament. The final HUD was a complete overhaul, with no similarities to Tournament being found.
The Ion Painter uses the same model as a previous, unnamed weapon, from the Championship betas, which just shoot energy bullets.
The Assault Rifle was a stronger weapon.
Many maps ended up being cut or totally different than the beta versions:
CTF-Lethargic is the only map from the UT2003 betas (which aren't test maps or retail/bonus pack maps with changed names) which didn't made the cut for either 2003, Championship or 2004.
BR-DE-ElecFields and CTF-DE-LavaGiant2 weren't finished before the launch of 2003. These maps were launched eventually in the DE Bonus Packs, and, the former is even one of the retail maps of 2004. The latter couldn't be included in 2004 or any later release due to a rebuild problem, though this being Unreal, a fan eventually fixed the map and ported it over himself.
CTF-Smote and DM-Gestalt weren't ready for 2003, but both were finished for the retail version of 2004.
BR-SlaughterHouse started as a CTF map.
BR-IceFields, BR-BiFrost and DM-Oceanic were called BR-Kalendra, BR-Endagra and DM-Vidona respectively.
DM-Compressed had two big pumps in the center of each circular room. This version made the cut for Championship, but not for 2003 or 2004.
DM-Molten was considered for 2003. It was released for Championship.
There was consideration for "survival guides" in 2003. Championship features a version of it.
Some promotional videos and screenshots for 2004 showed two extra maps for that game which didn't made the cut: ONS-Rise and ONS-Thor.
Another map which wasn't ready for the launch was ONS-Icarus. It was, however, released for free, and was the first "ownage" map, community maps chosen by Epic as "recommended".
Other maps which were removed from development were CTF-DuneBridge, ONS-AlienWorlds and ONS-Layn.