It's that the serial was cut down to a 75-minute single episode, down from the original seven 25-minute episodes that's the real draw.
"Doctor Who: The Daleks in Colour" courtesy of the BBC
It's fascinating to watch this early version of Doctor Who when they were still figuring out what the characters were The Doctor (William Hartnell)[...]
The Daleks in Colour Archives
Next week sees the British TV premiere of the first-ever Daleks story in Doctor Who, "The Daleks," only it's "The Daleks in Colour," a remastered, recut, and colourised 75-minute cut of the original serial, and the BBC has released four stills from the new colour version of the story And… those floors are blue[...]