I was curious so I began adding the differences between each game.

Before the link list, I purposefully don't include maps, mutators or characters except where it makes sense (UT2003 -> UT2004), because every game has completely new lists of these.

Anyway, I was curious to see how many changes were between games, aside of engine updates and the aforementioned maps/mutators/characters. Here's what I've documented so far:

• Unreal to UT
• UT to UT2003
• UT2003 to UT2004
• UT2004 to UT3
• UT3 to UT4

I'm totally, definitely sure I'm missing major details, as I wrote these lists hastily (I remembered the Jump Boots change in UT after doing the UT3->UT4 list), so if you see anything of note that's missing, I'm all eyes.