There appears to be a sample of a seagulls call at around 2:40 and again at 3:10. However these sound different from those sampled on "Happy Cycling".
There are also voices in the coda of this track. Between 5:16 and 5:35 is a recording of a woman talking and laughing. She laughs (5:20), says what sounds like "You know, this won't last..." (5:22-5:24), "I didn't like ... that before (?) ... times(?)" (5:28-5:30), laughs (5:32). It sounds like a sentence of some sort but a lot of words drop out. These voices are sampled from an early 1970's anti-drug social hygiene film. 
There are unidentified "samples" of computer game like noises near the end of the this track.
"Chroma key" (or color key) is a technique used in video production to swap in a separate signal source over a particular chrominance range across the source video, e.g. in bluescreen cinema effects.
The title also seems to be a reference to a musical by Tim Rice and Andrew Lloyd Webber called "Joseph and the Amazing Technicolor Dreamcoat".