Plot hole: Right after Bond escapes Blofeld and joins Tanaka and Kissy, they say they need to get to the Control Room (that Bond just left from), they look at the "front door" to the Control Room and Tanaka says "Impossible! It's too well defended!". Why did they not go back the way Bond just came from, through Blofeld's "apartment"? Instead, they fight their way across the entire launching complex and go through another entrance, which ALSO leads through Blofeld's "apartment".
Continuity mistake: When Bond and Kissy jump into the ocean to avoid the poison gas in the cave, you can see Bond's skin through his shirt. When they come ashore on Blofeld's volcano island, Bond takes off his shirt to reveal a grey ninja outfit underneath, complete with huge rubber suction cups for his hands and knees. Where did he hide all that?
Continuity mistake: At one point, during the scene with the helicopter dogfight, the tail wing of Bond's mini-copter is riddled with bullet holes (and yet the mini-copter continues to fly very efficiently), but for the rest of the scene, the tail wing is in perfect condition with no sign of the damage done to it.
Continuity mistake: In the scene at the end where Bond is trying to make Blofeld's spaceship blow up, you can see the timer showing the time till interception. On the 1st shot the timer shows 25 seconds. On the second shot it says 13 seconds. Then there is another shot and the timer shows 24 seconds.
Factual error: In the scene where the ninjas are attacking the volcano, they are armed with rocket guns. While the rocket guns, MBA Gyrojet Rocket Carbines, are real, their 13mm rocket cartridges could barely beat out a .45 ACP pistol cartridge in stopping power, not to mention they couldn't cause huge explosions like they did in the movie.
Plot hole: In the volcano base, Bond finds and frees three captured astronauts - two Russians and an American. But when they enter the SPECTRE astronauts' room, there are only two of them with Bond (and there is no indication that the third one was seriously hurt in the previous struggle with the guards); and after Bond is dressed in the spacesuit, they disappear from the story altogether.
Other mistake: When James Bond is in Tanaka's underground train enjoying the sake wine. One servant enters saying that the photograph is ready for viewing. This servant then walks to the door, which is on the left-hand side of the carriage. After going through the door, we can see the servant taking a left turn, but where to? Outside the moving train?