At 1:43 on the DVD, notice that the current Moonbase commander is Colonel Virginia Lake...seen in the Moonbase women's ubiquitous purple wig for the first time! It's hard to recognize her as the same woman! 

As Straker walks into his film studio office at 5:26 on the DVD, notice he has a wall of shelves to the right of his desk that has a number of metallic statuettes on it. These look like the type of statuettes given as awards in the entertainment industry, presumably for films and television series produced by Harlington-Straker. 

This episode reveals that Straker was an astronaut in the past and that it was he and Collins who put the SID satellite up in orbit.

At 9:20 on the DVD, Foster and Lake appear to be rather friendly with each other and they pull away just as Collins walks in. "Timelash" also suggests an attraction between Lake and Straker, though nothing is ever shown to come from it. Recall there was also the hint of an attraction between Straker and Nina Barry in "Sub-Smash".

The picture seen hanging on the wall in Colonel Grey's quarters at Moonbase is a variation on the one seen in Straker's movie studio office throughout the series. Somehow a picture of lips seems more appropriate in a movie studio than in SHADO's Moonbase!
Moonbase	Harlington-Straker Studios

At 24:11 on the DVD, a model of a 1960s-era U.S. space capsule is seen on the table in Grey's moon quarters. 

At 33:25 on the DVD, Dr. Jackson is showing Colonel Grey the results of Collins' time in the isolator. Notice that the device sitting on top of the equipment stack into which he inserts a data cassette has a knob with settings labeled "ON", "VOLUME", and "OFF" and the cassette is a standard audio compact cassette...inserted backwards!

At 34:33 on the DVD, what appears to be a silver-colored model of a U.S. Saturn V rocket is seen in Collins' apartment. Collins later uses it to strike Grey.

The shot of the rocket at  on the DVD is borrowed from

At 38:03 on the DVD, the same rocket appears here as was earlier seen in the the Anderson film Journey to the Far Side of the Sun. The launch pad area is slightly altered.
Launch pad in Journey to the Far Side of the Sun	Launch pad in "The Man Who Came Back"

The shot of the ambulance at 41:14 on the DVD is the same one used in "A Question of Priorities".

At 41:42 on the DVD, the wires holding the spaceship model are visible. And again at 44:30. 

As pointed out in the timeline of this episode at SHADOpedia, it takes place over the course of over 9 weeks.

UNANSWERED QUESTIONS

What of Dr. Jackson? He was last seen being menaced by Collins, presumably clobbered over the head as Grey was. Grey was found and taken to the hospital, where the doctors said he was lucky to be alive. But nothing is said about the fate of Jackson.

NOTES FROM THE DVD SPECIAL FEATURES

The DVD features three takes of "Singing S.I.D.", a performance of "Home on the Range" by Mel Oxley. Presumably, these were prepared, but left unused, for this episode, as a test of SID's repair. The concept of a singing computer was probably borrowed from the 1968 film 2001: A Space Odyssey, in which the Discovery's computer, HAL, sings "Daisy Bell".

MEMORABLE DIALOG

I've been hit.wav