Revealing mistake: In the scene where the launch platform is moving in Blofeld's cave to move the rocket to the Volcano crater for launching, there is a close up of the platforms wheels. Some are moving in the right direction,others aren't moving at all,making it look like the plastic model that it was. If it was a real platform, the weight alone would have made all the wheels turn in the same direction.
Audio problem: During the scene where Bond has to make his way back into the control room, he asks Tiger Tanaka to cover for him. Tiger does so with an MP-40 submachine gun. It's the loudest gun on screen when Tiger is firing it and has the MP-40's distinctive clatter. So far, so good. However, watch the gun's muzzle flashes (the MP-38, MP-38/40, and MP-40 as well as the MP-41 all have cyclic rates slow enough to distinguish between individual shots). When Tiger fires the first burst out of the gun, it corresponds perfectly well with the muzzle flashes. However, after cutting to Bond and then back again to Tiger, something went wrong. The muzzle flashes don't correspond at all to the firing noises from this point onward. In fact, when Tanaka takes his finger off the trigger momentarily to presumably prevent muzzle climb or let the barrel cool for an instant, the firing noises keep going.
Continuity mistake: In the scene where Bond is trapped in the light airplane flown by Osata's female pilot, she sets the airplane on fire and bails out. As she's exiting the plane, its landing gear is down. Once Bond frees himself and tries to recover the airplane, the landing gear is back up.