Again, they don't mention the violence. What, you can't kill people in this game?
Also, 18 is a very strong rating. I can't believe Nintendo would let it though I've especially noticed that Nintendo doesn't like swearing on their systems much. Even the Gordan Ramsey game was cut down to minimums. This game must be really pushing the boundaries.
No censoring was done.
Source
This also proves that there's only 2 hours of cutscene footage. If there's the standard 75-100 missions, then that's only 30 seconds of cutscene approximately per mission. Very fast talking, anyone? Or maybe it's just text, like GTA Advance.