OSR House Rules and Such

Village on Haunted Lake by Punknroll of Deviantart

This Saturday I finished DMing the climactic part of my Solo Heroes Labyrinth Lord campaign.  Allegra, paladin of the Red Hierach, met the army of the Winter King on the field of battle.  Successfully she united the forlorn realms and city-states of East Brendor against the 250,000 strong horde of berserkers and giants.  The Winter King was a warlord legendary for his cruelty, his very touch capable of encasing one in a tomb of ice.  Allegra fought all manner of terrible beasts and witnessed many forgotten secrets most folk would not experience in several lifetimes.  Her horse is a celestial being and divine gift, her sword imbued with the spirit of Su'ursgah the fire elemental famous for centuries-long battles against evil.  She's seen necromancers call up the bones of elder beasts, only to put them back into their graves.  She's healed the tainted ley lines within the blighted forest and wiped out the remnants of the Shadowguard.

And this was all done in the span from levels 3 to 7.  After this session it's likely that I'll be taking a break from this world, although unlike Arcana High it's possible we may come back to it to record more of Allegra's deeds, especially if the upcoming Dreams of Ruin adventure is an exemplary module.  This campaign was my first real long-running OSR game, and I took sincere joy in creating a world modeled off of old-school aesthetics while at the same time applying my own inspirations and changes.

Below are the house rules I used on a regular basis for this campaign.  Some of them are streamlined rules conversions from newer editions which we found more intuitive (both of us cut our teeth on 3rd Edition D&D), or simply modifications which felt right for the campaign.

Ability Checks

Inspired by D&D Rules Cyclopedia.  A D20 is rolled when the PC wishes to perform a task with a reasonable chance of failure not covered by spells or class features.  The result is compared to the ability score most relevant to the task at hand.  If the result is equal to or less than the score, the task succeeds.  If it is greater than, it fails.  For particularly easy or difficult tasks, a modifier ranging from -4 to +4 is added to the D20 roll.

Rationale: This was used for the times when Allegra wished to climb treacherous walls, spot hidden danger, research obscure lore in libraries, and the like.  It rewarded high ability scores by making the PC an expert in a general field of expertise.  Those with high Intelligence were veritable storehouses of knowledge and could remember plenty of detail, high Charisma characters would come off in the best light for their player's intentions, etc.

Special Materials are "Magic"

A monster's hide or magical barrier might be so strong that only an enchanted blade may hope to smash it; or perhaps one fashioned from adamantine.  Armor made from the bones of an elder beast is particularly resistant to the elements, and can grant limited protection from breath weapons and fire and ice spells.  Elf-forged weapons and armor are incredibly light but do not sacrifice durability, weighing half as much as their iron counterparts.

Although such materials are not treated as magical for the purpose of divination spells and register as 'normal' pieces of equipment, they are considered magical for the purposes of a monster's damage immunity and resistances vs. non-magical weapons and armor.  If a set of dragonbone plate was crafted by a dwarven forgemaster instead a wizard, that does not mean it can't have a +2 bonus.

Initiative

Personally I found Labyrinth Lord's procedural order of turns based on weapon type to be more complicated than Pathfinder's number-based order.  When combat starts, the PC and each class of enemy rolls a D20, with a bonus or penalty in very rare situations for extremely fast or sluggish creatures.  The person with the highest result goes first, regardless of whether they're using a melee weapon, ranged weapon, or spell.  They're followed by the next character or class of enemy with the next-highest result, and so on and so forth.  Ties are resolved via a second roll-off.

A class of enemy counts as a group of characters who share the same properties.  For example, a fight with four goblins and a dragon would have the goblins' initiative rolled only once, but the dragon rolls separately.

New Equipment

Bio-luminescent Fungi: As most Underdark cities have a natural ceiling and thus no easy place for smoke to escape to, typical torches are banned and inhabitants make use of naturally glowing mushrooms hanging from baskets.  A patch of such fungi clearly illuminates out to a 30 foot radius.  The fungi needs to be fed with 1 gold pieces worth of compost every 24 hours or else it will shrivel up and die, no longer giving off illumination.

Repeating Crossbow: This crossbow has an attached box on top holding five bolts, allowing the wielder to fire projectiles without the need to reload between shots.  They deal 1d6 damage per shot and weighs 6 pounds.  Once the battery runs out it must be detached and refilled, which takes 2 turns.  Repeating Crossbows are advanced technology and thus not sold in all lands, but cost 100 gold pieces where they can be found.

This weapon saw effective use among the manticore riders of the Winter King's forces, who Allegra fought when assaulting one of their citadels.