Goofs

The incident involving Buzz Aldrin's bio-med sensors going out, leading him to crack wise, saying, "I promise I will let you know if I stop breathing," occurred during the return voyage, on day 8 of the mission, but is depicted (at approx 48 minutes into the film) as happening during the approach to the moon before the separation of the command and lunar modules.

During the radio check before launch, at 15:44 they ask for a check from CMP and then greet Buzz Aldrin. Mike Collins was the CMP (Command Module Pilot); Buzz Aldrin was the LMP (Lunar Module Pilot). You'll notice they didn't include the audio of the radio check with Mike Collins, so audio clips were likely spliced together.

Near the end where the Command Module is returning to Earth, a Grumman E-1 Tracer aircraft is shown flying and the sound effect is jet exhaust. The E-1 Tracer was a piston prop aircraft and never featured jet engines.

At 0h11m the footage of a Sikorski H-19 helicopter flying along the beach is shown, followed by the footage shot from the inside of the machine. For both these shots the sound of a gas turbine engine (similar to the sound of a vacuum cleaner) was used. H-19 helicopters however used radial piston engines and sounded similar to an WWII era fighter plane when flying.

Conversations between the astronauts and ground controllers are depicted without any response delay between the parties. In reality, signal propagation time between earth and moon is about 1.25 seconds, one way, or about 2.5 seconds round trip. The conversations in the movie sound "natural", but in fact had noticeable pauses in real time.

When the returning Apollo 11 blasts away from moon orbit, there is a dual visual display showing elapsed rocket burn time and spacecraft speed. The speed rapidly increases to just over 5500 mph during the rocket burn, and then the rocket cuts off. But the speed continues to increase for a few more moments. In reality, the speed would have stopped increasing the instant the rocket cut off. This is not an error as the residual bleed of the engine slowly being shut off will result in a slight continuation of acceleration.

During the entire descent of the Eagle to the surface of the moon, the screen shows 14.745 meters for the inn.