There are two kinds of difficulty, fake difficulty (primarily arising from having the adversaries cheat) and real difficulty. This game unfortunately includes both varieties in a particularly tedious and hassle-filled combination.
On the one hand it features enemies that can do all the same things your characters can (including instant-death attacks) in great numbers (encounters range up to groups of 18). This is real difficulty. On the other… it also gives enemies abilities your characters can’t possess (even if you Summon Contract them; such as formation switching), gives them infinite spell casting, resets your attributes to the racial (not class) minimums if you multi-class, has equipped items reduce your free carry space, completely disallows resting outside of town, and restricts having a basic map to a specific spell/item (L1 Mage/Magic Map). That’s all fake, artificial difficulty.
The two real deal killers are the map system, since the environmental graphics are incredibly bare-bones and floors are filled with miles of identical walls and doors which inexplicably auto-close behind you (more fake difficulty), and lack of a dungeon-based resting system which makes primary spellcasters dead weight most of the time… unless you had the fore-knowledge to make them Dragonewts for the Breath attack. It also doesn’t help that leveling is unexciting; apart from gaining new spells (which you’ll rarely use in normal encounters) the only other useful level-up abilities come from ‘mastering’ a class at level 26+.
If all that wasn’t enough though, there’s also the technical issues. Sometimes left-clicking won’t work as a selection command (such as when transferring items between characters) and you have to use the relevant keyboard command instead (Enter by default), using the ‘repeat last round commands’ function does not repeat the character ordering if you set it, the identify/disarm traps menu is a clunky mess, and the town menus are an unintuitive labyrinth.
So no, I don’t think I’ll be playing any more of such a highly random and deliberately antagonistic game. Some resources if you decide to attempt it:
Useful Information and Walkthrough
Cheat Engine Table (GoG Version)
Age Stat Growth and Spirit Pact Information (GoG Version)