Officially you only actually had to kill one person (depending on ending) but there was actually a way to complete the game without killing that person, video is on youtube if your intrested, involves catching a gas grenade and the exit door gets opened for you....

It was Hong Kong not Tokyo, i liked it somewhat but i think it was mainly all the loading areas that did my head in, my least favourite part would have to be right at the start of the Paris level...