Dev

If you think Sierra games are unfair, your just too young and weak - that's the way games were in those days ;)
Nah, to be honest you can't judging her by todays standards. To understand the genius, you have to think back to the early days of  adventures. Text adventures. No pictures. Sierra changed that. Inventing it is quite a contribution to the genre of graphic adventures, isn't it ?
The difficulty can also be explained with these roots - in text adventures a large part of the fun was to find out what you are actually capable of doing. Sadly they sticked to that mechanic until KQ 7 ....