The word "inappropriate" is used, and it sounds like the major change involves the side quest, The Power of the Atom. In this quest, you can choose to either disarm the nuclear bomb sitting in the middle of the town called Megaton... or you can arm it to explode.
In the Japanese version, rigging the bomb up to blast will be removed as an option. This will also have the side-effect of making it a bit tougher to accrue a ton of negative karma near the beginning of the game. Hey, it ain't easy bein' the bad guy.