Reading through the manual I've come up with the following I'd like to see...
"The story so far..." Would be nice. I don't really think the different endings from Book I should make much of a difference here; it's usually commonplace to just pick an ending and expand upon that for the sequel. Of course, if Book II starts us of with a different main character then it could even be as simple as "While so and so was off gallivanting in such and such a place.... this was happening elsewhere."
A partial list of monsters, spells, and equipment would be an excellent addition. I realize that it would be ludicrous to expect a full list of equipment given random magical modifiers, and completely understandable why you wouldn't want to list all the spells and monsters. Still some samples would be appreciated.
While the character classes are pretty obvious, something more than "- Fighters get the Sword Skill " for a class description would be favored. I understand that this is an "Old School RPG" style game, which uses your cookie-cutter character classes, but it's always nice to read a description that's flavored with background from the game. Consider the following:
The Fighter class encompasses the most common type of adventurer in the realm of Thaermore. They tend to favor the close quarters of melee combat and generally focus on Strength, Dexterity, and Endurance for maximum survivability and physical damage. The basic training of the Fighter gives him/her starting proficiency with a Sword, although it is not uncommon to see a well sharpened axe or imposing hammer in the hands of such an individual. They often sport heavy plated armor and large shields, which can give the appearance of a walking fortress. Fighters who do not desire to adventure are often seen in the ranks of the military or filling the roles of the town guardsmen. There are also those of the less savory sort who've turned to lives of crimes and become brigands that harass the local populace, often retreating into the Great Tangletree Forest where local authorities are lax to follow. If one thing can be said for certain, you'll want a Fighter to have your back during a brawl at the local tavern.
CrazyBernie finally came to a crashing halt after sliding down the mineshaft that suddenly opened beneath his feet. "Damn, that's gonna leave a mark," he groaned as he dragged himself out of the rubble. After dusting himself off somewhat and adjusting his chainmail shirt, he lit a torch he had in his now torn up rucksack. The light from the torch penetrated some of the darkness, illuminating several pairs of eyes that stared at him intently. "Rats," he sighed. "The Catacomb variety judging from the size." He spat on the ground, and drew out his longsword. "Well, might as well get this over with so I can look for a way out of here."
Didn't take terribly long to come up with, yet adds a wealth of dimension for those Manual Lovers (you know who you are).
Also, the "Committing Crimes" entry in the Book I manual seems strangely out of place between "Combat" and "Using Magick and Casting Spells", as though it was just tossed in anywhere as an afterthought. Perhaps there needs to be an "Interacting With NPC's" section?