One of the three tapes is not a game tape but is the "siphonic sound tape" soundtrack to be listened during the game. The game instructs to play a specific music whenever necessary.
Game https://www.amusement-center.com/project/egg/game/?product_id=174
Soundtrack https://www.amusement-center.com/project/emusic/cgi/eggmusic_catalog-detail.cgi?product_id=5354