During the descent to the underwater habitat, Harry identifies the classical music inside the mini-sub as: "Mozart. Horn Concerto in E-Flat, K447.", which is not correct. It is Wolfgang Amadeus Mozart's Horn Concerto in D, K412.
After Harry went in the sphere Barnes turned round and accused Norman of screwing up their trip to the surface in other words saying it was Norman's fault that they were not going up to the surface when Norman had nothing to do with it was Harry's fault due to Harry going to the spacecraft when they supposed to be up to the surface.
When Beth opens the cupboards to show Norman that there is no food, she opens the left door and then the right, and when she closes them the left door stays closed but the right one swings open a little bit. The camera cuts to Norman, and when it cuts back to Beth the left door is open and the right one is closed.
When Harry and Norman are talking after the scene in the eating area, and Harry tells Norman they are going to die down there, Harry lies down in his bunk. The first shot shows Harry lying with his head on the pillow and the next shot shows Norman from Harry's perspective and his right foot is hanging over the bed. As the conversation ensues, Harry sits up in his bed and is clearly seen leaning against the wall, which means his legs should have moved up too. The next shot of Norman shows that Harry's right foot is still hanging over the edge.
After Harry saves Norman when he has a valve leak and is attacked by a sea snake, there is a sky shot of Harry telling Norman to breathe normally. In the last few seconds of the scene you can clearly see in the lower left hand corner the leg of a crew member wearing shorts with black and white sneakers.
When Jerry first makes contact, he transmits in code : "MY NAME IS JERRY".
Later, the code is revealed to have been mistranslated and the message reads: "MY NAME IS HARRY"
If the letters H, E, J, and A in the simple letter/number substitution code were wrong, the first message would have read: "MY NEMA IS JERRY".
Also, the entire series of conversations they had would have exhibited the same error, yet none did so. (HAPPY would have been JEPPY, ALL = ELL, etc.)
The team needs to decompress each time that they enter the sub/ habitat module/ spaceship while scuba diving, which at 1000 ft, actually takes ~15 hrs. There is no need to decompress on board the surface ship since the sub's interior air pressure is always ~15 psi (1 atm) during the entire ascent (and descent) - as are presumably the habitat module and spaceship.
Ted sees Harry in the shower, and Harry is singing. He doesn't have on his voice adapter. So, Harry's voice should be very high, due to the helium in the air. However, his voice is perfectly normal.The voice adapter is the small box on the silver chain worn round their neck, the chain is clearly visible round Harry's neck.