From publisher blurb:
The Nightmares Underneath is an old school role-playing game with a strong horror theme, set in a fantasy Middle East where dungeons are invading nightmares intent on the destruction of civilization.
In the Kingdoms of Dreams, all is right with the world—except for one thing. Even though the Law has triumphed over the powers of Chaos, banishing idolatry and superstition in favour of science and reason, humanity is still threatened by a dangerous, otherworldly force. The Realm of Nightmares invades the physical world, sending incursions in the form of dungeon to undermine and destroy society.
The Nightmares Underneath conforms to the following common assumptions of other old school games: six attributes, 3d6 in order, class and level, xp for treasure, spells are memorized, and there is a simple system of rolling under your attribute scores for saves and skill tests.
Some aspects of the game are less common:
Initiative is rolled again each round, but only by the players—monsters always use the same initiative scores.
There are 5 alignments, instead of the usual 3 or 9, and they affect the way a character interacts with magic and social institutions.
Instead of hit points, this game uses a Disposition score, which you roll for each day of adventuring. Once your character runs out of Disposition, instead of dying, successive damage reduces your attributes, and may cause you to be crippled, maimed, or knocked unconscious before being killed. The special attacks of monsters may also reduce your attribute scores instead of causing normal damage.
So what is unique about The Nightmares Underneath?
Nightmare DungeonsThe justification for dungeoncrawling in this setting is that adventurers are raiding nightmare incursions, to find the treasure that keeps an incursion anchored to the physical world. Once the treasure is looted, the incursion is destroyed, and the adventurers profit. Individual creatures made of nightmares can be killed, but as long as the incursion exists, it will continue to spawn more. This is reflected by a countdown die, used in addition to encounter checks for wandering monsters.
The rules also include procedures for creating nightmare incursions, the creatures that stalk them, and how they grow larger and more dangerous the longer it takes adventurers to deal with them.
Nightmare CursesThe terrible experiences adventurers face inside these nightmare incursions can leave lasting damage in the form of nightmare curses. When the darkness creeps into your soul, the result is madness, or supernatural restrictions, or even physical changes.
The players’ characters only suffer these curses when they are severely injured inside an incursion, while normal people can be driven mad simply by being inside an incursion to long. Be careful what hirelings you take into the dungeon with you!
Social InstitutionsOnce the dungeons have been looted, the carousing chapter includes guidelines for investing money in social institutions that can then provide favours and much-needed services to adventurers later on. Once you’ve spent enough money in town, you can attend classes at the local university to become more intelligent, the local druggist starts stocking the good stuff, and the geographical society lets you use its maps of the wilderness.
Characters can also turn communities against them, by committing crimes or leading villagers to their deaths inside the dungeon. Settlements have resentment ratings with each of the players’ characters, which may cause them to be forcibly driven out, if they get too high.
SpellcastingAny character may cast spells, though wizards are much better at doing so safely. There are 100 spells, and though they have levels, this does not restrict them to characters of specific levels, it only makes them harder to control. Beginning characters have the same chance of knowing any spell.
But you can always read it for yourself: this version is free and contains the entire text of the game.