I'm gonna have to go super old school on this, because I think gradually games have gotten progressively better about this as the art form advanced. The absolute worst for this that I know of for this has to be "Below The Root" which, despite this point of criticism was a mind-blowingly advanced game for its time, arguably the first real open world CRPG. I have no idea how anyone could've legitimately completed the game without either using a guide or playing it over and over for years to learn every possible route of progress. I think the confusing nature of the world was in fact simply because nothing of that scale had ever really been attempted before and there was absolutely no precedent for how to adequately guide players through it.

The world was, for its time, truly immense and sprawling with a multiple screen interiors for most buildings, a full cave system hidden underground, ladders and secret platforms aplenty. You could converse and trade with various NPCs in houses and wandering around on many of the screens. And when I say "screens" you have to keep in mind I'm talking about something this size. That is not a lot of context to work with for navigation.

It's also full of secrets and hidden things, and like many games of the time you will need to find and use pretty much all of them, in pretty much a specific order, to actually complete the game. I can't even describe how insane the sequence of events you need to do to actually complete the game is, this guy uses a guide and save states but I think it illustrates the general lack of clear guidance in almost all cases. Combine that with the fact that you "die" easily, your inventory is extremely limited capacity, and did I mention you're on a time limit? Because the "goal" of the game is to rescue a guy and if you take too long, he dies and you can't win anymore!

Many naive players (myself included) weren't even convinced it HAD an ending and just kind of played it endlessly like it was some early version of The Sims.