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 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.
Plot hole: When Quatermass is being admonished by the senior minister for talking to the press, Breen gives his own theory to explain the presence of the spaceship: He says that it was used a propaganda weapon in 1944 and that the figures inside were made up of scraps old skin and bone, why was he unable to explain how the hull of the spaceship was heat resistant up to 3,000 degrees and harder than diamond?