I played this when a student back in the early 90s (on my old Atari ST). It kept a house full of gamers puzzled, entertained and amused for many days. I can't recommend it highly enough :)
There is a strong Hitchhikers-type sense of humour throughout so whilst you may get frustrated you will always be laughing.
Play it and say goodbye to many hours you could overwise spend constructively but you will never regret it.