I had hard time going through Necrohol of Nabudis, mostly because I was underleveled, those human like creatures were avoiding my attacks like their were nothing, I was constantly healing my characters though for nothing in the end as one of the rare games killed my party with ease.

Great Crystal is another location I'm not really fond of, the entire place was a huge maze and lack of proper map made things worse, you could get easily lost in that place.