bolotnik,
I think I already told you about Longest Journey: I also failed to complete it the first time, I reached the enemies too late, and there was an annoying mistake. The second time, I completed it. It's a good, classic map, but not too difficult.
Otherwise, I completely agree with what was written.
The most difficult RPG map that I couldn't complete is Paragon...
It's really a very difficult map (especially when playing without Expert Fire; it might be a little easier with it).
At the beginning, you need to capture Virill and defeat Frodaragon by the 3rd month, but even after that, you can't relax; one group attacks, then another....
And you can't lose anyone.
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I downloaded the "Battle of World" map, but I haven't played it yet.
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I hope to tell you about the one I'm playing.