Beneath Nightmare Castle is #25 in the series. It has four stats: Skill, Stamina, and Luck function like in the other books, and a Willpower stat is added. You generate Initial Willpower the same way as Skill or Luck.
Food exists in this gamebook, but you start with none; the book implies but does not clearly state that you can eat only when specifically permitted to by the text. You do not start with a potion. Your starting equipment is "your armour, your sword and your backpack." You explicitly have no food and "very little" money. (The book clarifies exactly what "very little" means before you have a chance to spend any.)
1: Unless you rolled badly enough that you really want to die so you can reroll your stats and start over, trust the unknown voice. (You can insta-die earlier in this gamebook than in any other I've written a walkthrough for to date.)
331: Escape up the staircase. (You have two chances to insta-die earlier in this gamebook than in any other I've written a walkthrough for to date.)
119: Reveal your association with Baron Tholdur.
164: Show him the ring. Also, note on your Equipment list that, contrary to what you were told earlier ("only your armour, your sword and your backpack"), you have the ring.
179: Take the innkeeper's advice and stay in.
245: (Gold Pieces set to 5) Walk about the town.
137: Temple Quarter first, as per the innkeeper's advice.
195: Visit the last temple.
322: Hide in the rocks and watch the temple entrance.
263: (Gain Potion of Berserk Rage) Accept the invitation.
398: Give him the ring. (Lose Ring)
344: (+4 Stamina, Gain 3 Meals)
100: The Ordeal is a risk you shouldn't take.
108: Head to the Merchants' Quarter.
32: This Luck test is important. If you fail, you lose all your gold, and should head to the riverside at your first opportunity; note that you will not have the Trident of Skarlos in this playthrough. If you succeed, let the girl flee from combat and go back to looking for food.
149: If you still have money, buy three meals. (-1 Gold, +3 Meals)
280: Buy a piece of old junk from the street trader.
129: Yes, you do want the handleless garden fork. (-3 Gold, Gain Garden Fork)
237: Go to the riverside area.
90: Hide and spy.
336: Wait and watch.
114: Look at the crate.
259: Push the crate off the jetty.
294: (+1 Luck)
377: Time to go to Neuberg Keep.
289: Take the right-hand trail.
95: Turn right.
175: Enter the base of the battlement tower.
284: Investigate the compost heaps.
153: Put the globe in your backpack.
44: Enter the tower.
394: Climb the stairs immediately.
51: Yell that you've killed the Ogre.
235: Tell the dwarf about your quest.
312: (+1 Luck) If you have food, offer some to the dwarf and ask for a preparation to bolster your Willpower. Either way:
396: Head down to the cellars.
25: Stay in the main passage.
248: The book tells you you randomly decide to do something dangerous. If you get the poisonous barrel, don't look inside.
127: Either choice here will lead you to:
392: Go quietly.
64: If you have the Garden Fork, take it out. If not, wait quietly for rescue.
362: Pry up some flagstones.
80: For some reason, this book keeps giving you chances to turn back. Descend into the darkness.
170: While a strict reading would indicate that having the green globe requires you to turn to the entry listed for it, because it's listed first, that entry presumes you're using it as a light source even though it's not the light source you chose back in your cell. Decide which entry you can, in good conscience, turn to. If it's the green globe entry, "return" the globe to your pack immediately and look at the large wooden door to your right. Use the Garden Fork to unlock it.
7: The priest told you who rules here now. Call out "Xakhaz."
258: Continue down the steps.
109: (+1 Luck)
16: Snatch the length of blue metal.
182: (+2 Willpower, +1 Luck, Lose Garden Fork, Gain Trident of Skarlos)
240: Return to your cell.
206: Say that you are on a mission to cleanse Neuberg of evil.
29: (Gain Talisman of Loth) Demand more information from Cernic.
376: Go down the stairs.
300: Slink down the right passage.
155: Await developments.
126: Sneak through the doors.
213: Go through the left door.
387: Eat and go through the other door from this room.
115: Delaying here would be fatal. Walk into the web.
89: Cernic warned you never to expose the Talisman while looking in a mirror, and it would be foolish to give the wizard who has enchanted Baron Tholdur a chance to do the same to you. Attack her without hesitation.
160: Inspect the box.
131: Z is for Zagoula, X is for Xakhaz. You want to destroy Xakhaz; you don't want to be teleported to the city of Zagoula. Push the rod toward X.
335: The mirror isn't dangerous as long as you're looking away from it. Go ahead and reveal the Talisman.
27: If you have the Trident of Skarlos, avoid fighting the warrior. Either way, go through the doorway at your earliest opportunity. If you have not yet drunk the Potion of Berserk Rage, you should do so now.
389: This Willpower test is important. If you fail, you'll have a fight on your hands. If you succeed, quickly pull out the Talisman of Loth and the green globe. Either way, good luck, hero!