Versions
Resident Evil 4 was, at first, developed and designed exclusively for the Nintendo GameCube. Late in the development cycle, Capcom announced that Resident Evil 4 would make an appearance on the PlayStation 2 as a port (with a few extras).
Because the PlayStation 2 version had quite a bit of extra time for development, a number of special features and changes were made to the game. Most of these changes are not significant and do not affect the overall plot or story of Resident Evil 4. You'll find very little in the way of main story differences between the Nintendo GameCube and PlayStation 2 versions.
In addition to the two versions available on the PlayStation 2 and Nintendo GameCube, the game underwent further change before it's release in Europe. The German version had the most changes applied to it, with much of the game's content being censored and/or cut.