To be sure you understand the context in which the following applies, read my proposition for the campaign and possibly the description of the available classes (it comes particularly handy for typical exploration activities).
To put it simply, the game consists of the following parts: (1) first, the players are given information about the dungeon so they can plan ahead, buy proper equipment, and hire qualified followers; (2) then actual dungeon crawling is resolved with exploration, friendly encounters, and deadly combats galore; (3) finally, they return to base, sell loot, and spend some money. Below, you find detailed description for each stage, procedures that have to be followed, and some of the rules that help resolve the situations that arise.
I present the players the list of rumours they can hear and quests they can take (actually, these lists are going to be available prior to play so that players can read them and think about their options; planning is very important but we also want to spend most of our time exploring the dungeon). Usually 3 to 6 quests are available at a given moment, each associated with a different NPC; quests also grant two different types of rewards, one in-game (gold, magic items, treasure maps, services, discounts) and one meta-game (I am thinking of 4 points for each quest completed, but it may be treated on a quest-by-quest basis).
It is advised that the party plan ahead, discuss their interests, and spend their hard earned money accordingly. You do not need to formally announce which quest you undertake and there are usually no repercussions of failing one (there may be quests which are different but this kind of information will definitely be included in their descriptions); however, determining what you want to accomplish is crucial. You want to maximise your efforts and focus on a few things only; it will be much more rewarding than purposeless wandering (although scouting ahead can also be very productive in the long run).
There are a number of followers available for hiring, each with a unique set of skills, abilities, and equipment, that make them very useful for an adventuring party. At any given time, there are 2 to 12 different followers available; some may then seek adventure elsewhere and become temporarily unavailable, but then others will come.
Following the pattern outlined by Brendan, there are a number of uncommon items (1d6), rare items (1/d6), and special items available (besides the ones in the Kazamaták és Kompániák rulebook), rolled on a random table of my own design. These items can be purchased just like regular (common) items but their quantity is more limited (actually, followers are to be treated in a similar manner).
When you decide not to buy anything else or hire followers, and you agree where you want to go/what you want to do in the dungeon, the next stage of play commences.
First, you need to decide through which entrance you delve into the dungeon; at the beginning of the campaign, only three of them are available, but more can be discovered through play. Once the party enters Rappan Athuk, dungeon exploration begins.
Time is tracked in two measures: turns in exploration mode and rounds in combat, the lengths of which are decidedly kept vague (although 1 turn equals 10 rounds if becomes an issue). Generally, wandering monsters are checked every turn (there is a 1 in 6 chance of encountering them).
Characters can fully function for a limited time only; after five turns spent exploring, they start to gain a cumulative -1 penalty every turn, until they spend a full turn resting uninterrupted (roll for wandering monsters normally). Two consecutive turns of resting also restore 1d3 hp.
Below are some common actions players can take while exploring. Most rolls are successful if the result is 5+ but there may be exceptions (the underlying structure was inspired by the Apocalypse World engine and Alex's post).
- force a door open: 1d6+STR, takes 1 turn, renders the door useless, and triggers an extra wandering monster check due to the noise; on a success, choose one: (1) it takes only 1 round, (2) the door remains usable, or (3) you do it quietly and avoid the extra wandering monster check
- pick locks: 1d6, takes 1 turn, requires thieves tools; on a failure, you break your tools
- disarm traps: 1d6, takes 1 turn; on a failure, you activate the trap
- listen at doors: 1d6, takes 1 turn; on a success, you are able to determine if there is anyone beyond, their approximate numbers, and whether they are intelligent creatures or feral beasts
- climb sheer surfaces (without proper equipment or under attack): 1d6; on a failure, choose one: (1) you fall and take damage, (2) your backpack falls off, its contents probably lost or destroyed, or (3) after a full turn (or combat round) of trying, you acknowledge the fact you simply cannot do this, and you cannot try again until next session
- search through rooms: it is handled through discussion; when you enter a room, its visible contents are listed, and you decide which of those you investigate by asking questions and moving your character around; there may be several "layers" of information (think of text-based adventure games or read this)
Whenever other creatures are encountered, we resolve the situation using -C's On the Non-Player Character and a slightly modified version of Labyrinth Lord's combat system. These involve: (1) determining surprise and starting reaction, (2) rules for parleying, (3) group initiative, and (4) Target20 for attacks and defence. After combat, exploration mode resumes and the game continues.
Return to Town
When the party exits the dungeon, they return to their base of operations without further complications. There they are told the exact market price of every item they brought with themselves from the dungeon; magical items are also identified, their effects explained to the players. For each gp they make by selling loot, they also gain 1 XP; when summed up, they each get an equal share of it. Note, that magical items can also be sold for gp and XP; if kept for some time and sold later, however, players will not benefit from it XP-wise (they still get the money, though).
After their shares have been figured out and levelling up is completed, players have to decide what their characters do until their next foray into Rappan Athuk. Thieves are able to concoct poisons, while Magic-Users can create scrolls and wands. I was also thinking about implementing a training system of some sort (something along the lines of the Middle Road skill system) - but that would require further changes.