PlayStation: In the final cut scene, as Ethan is about to have an intimate moment with his female sidekick Candice, she was scripted to say "Oh, Ethan".
During recording of the German speech, Candice's voice talent, Anne Frank, tried to deliver that line several times in a seductive way, but miserably failed to convince the staff.
The people in the studio desperately searched for alternative lines; programmer Michael Krehan then, just for fun, came up with the line "Oh Ethan, you're cooler than James Bond!".
This line was never intended to be used, but since none of the other attempts sounded remotely convincing, Candice actually says "Oh Ethan, du bist cooler als James Bond" in the German version.
During development, X-Ample added a cheat ("RIZZIBIZZI") to the PSX version which would modify the textures of Ethan Hunt and Candice to show them in S/M type clothing. After Infogrames nearly freaked out, the textures were quickly removed. The cheat code is still being checked, but nothing happens if it is entered.
Sony USA insisted that the camera angles in the ingame cut scenes were modified to make the game look less like the N64 version. That's why the European version (which was approved before that) mostly has the original N64 cut scenes while the US version incorporates major changes that had to be made in the last minute.
PlayStation: Since game data is mostly the same on both the European and the US version, and because the game language is stored in the password, it is possible to play the game in Italian or German even in the US version: You just need to enter a password which was obtained by someone playing in that language.