Executive Meddling: A justified example, with the decision to change Largo's death from a gruesome harpoon through the neck, to a relatively more tame but more dramatic harpoon through the back.
The Other Darrin: Felix Leiter is recast yet again, this time with Rik Van Nutter, apparently doing his best Jack Lord impression. Possibly happened with the voice of Blofeld as well, as various sources claim that Joseph Wiseman (the titular Dr. No) took over the role from previous actor Eric Pohlmann in this film, while yet others say that it was still Pohlmann.
It was originally thought that the title would be too awkward to work into a song, so instead Shirley Bassey wrote one called "Mr. Kiss Kiss Bang Bang." This is why the club Bond runs into to escape Fiona's goons is called The Kiss Kiss Club.