There is no docs though and MODder didn't allow to reveal them on PK forum, lol. Runeword system is interesting, you can make any runeword in any rohling and they are actually words from english language (FORGE for example). Droprates are EXTREMELY low, even rare items almost never drop. Variety of monsters is bad, I thnik theres like 4-5 different monster per act, some of them repeat in different acts even. Gameplay wise it's very slow, feels like even slower than cLOD. Also, there is no synergies between skills, so useless skills serve no purpose at all. And since its normal, I can get only low level skills from those places, so it's annoying as fuck. But even there, dropprate for those sucks, and I can't imagine how would I farm them without tele skill (my char has tele skill). There is like 2 places to farm books more or less reliably, chamber of bones in a1 (2 gold chests) and 'arcane sanctuary' in a2 (3 gold chests). Also its ultra troll sometimes, I did roll book with punisher (my useless skill) + other class book and it rolled me punisher again. You can reroll two random books and get one with skill for your class, but again, chances of getting useful skill are low. What makes it even worse, that particularly my char has like ~10 useless skill, so chances to get something decent are even lower.

Another problem is that there is 7 classes, and so chance finding book which would fit you is even smaller. I think I found 2-3 books while going trough a2 and a3. Skill books are VERY rare, during playtrough they almost never drop. Skill system in this mod is screwed pretty hard.

To helfire and back