This game was due to be released by Psygnosis in September 1993 but never came out.
Indigo was originally born between 1991 and 1993 by Stephan Belin for the Atari ST, including the original concept, code, graphics, music and sound.
Dominico Manfredi did the Amiga port. To download it click here
More info here: http://www.stephanebelin.com/indigo/indi go.htm