For those wondering just how pervasive this is:
https://tvtropes.org/pmwiki/pmwiki.php/UnwinnableByDesign/Si...
https://tvtropes.org/pmwiki/pmwiki.php/UnintentionallyUnwinn...
https://tvtropes.org/pmwiki/pmwiki.php/UnwinnableByDesign/Si...
https://tvtropes.org/pmwiki/pmwiki.php/UnintentionallyUnwinn...
Sierra operated a 1-900 tipline (cost $0.75 per minute or similar). I can't imagine anyone beating these games without those tips or tips from a magazine.
You'd expect one or two of these things to slip through by mistake, but so many indicates it was a bizarre but deliberate design decision?
nah, you were supposed to buy official Hint Books https://www.sierragamers.com/hint-books/ or call 0-700 tip line. This cruel design printed money.