Interestingly, the game was reviewed by a German ST magazine, ST-Computer (http://stcarchiv.de/stc1991/10/relax-aktuelle-spiele). The article doesn't mention anything specific about the ST version and the author was known for writing lots of reviews of Amiga and ST games so it's not clear whether he really had the Atari one.
Music now in Sndh archive
Showaddywaddy - 30/10/2011
Yeah.. never released on the ST, though I do have some work on this sent by the developers :)
Sounds cool! Any chance to release that stuff?
Atarimania ST Team