Tunnel Generation

Way back in the day, that is 1982, a creatively named RPG company named Role Playing Games Inc., made RECON, a hybrid wargame-rpg about the Vietnam war where you get to play as SOG operatives traipsing through Laos blowing up motor pools and hunting down Charlies. It’s a flawed game but a lot of fun with the right group of guys. One of the supplemental books, Hearts and Minds, published in 1983 included a set of tables for randomly generating Viet Cong tunnels. I’ve used these tables to generate on-the-fly lizardman warrens and figured it’d be worth it to folks if I reposted the tables here. I will adjust some of the entries to account for a traditional d&d-esque fantasy setting.

Several changes have been made and I shall note them here:
All instances of NVA changed to Wandering Monster
All rooms have a 3-in-6 chance of containing a contact.
All rooms will receive a second roll on the first table to determine egress (or lack of)
Diesel-powered electrical generator to Lit room (with 1 lamp & 1-4 oil flasks)
Print shop to Chapel
Radio room to Runner’s relay station (with bed and rations)
Arms factory/repair shop to Repair shop
Ammo storage to Armoury
US Jet Pilot to Minor noble (or rich merchant)
US Heli pilot/door gunner to Lawful commander (F3)
Special Forces trooper to NPC with 1-4 HD
VNAF skyraider pilot to Lawful nonhuman
US Army grunt to Lawful soldier (F1)
US Marine to Sailor (F1)
Woodsman (F1, familiar with local area)
Civilian accused of spying to Villager (normal man)
French accomplice pretending to be American for propaganda to unintelligent creature
Communist Journalist to Evil man (normal man)

Air vent – pit trap that leads to lower level
Punji Pit – 1-6 damage, 2-in-6 of being diseased
Boobytrap – 2-in-6 chance of each: ceiling collapse (1-8, triggers wandering monster check), spear trap (1-6), pit trap
False Floor/Wall – elves and dwarves may automatically detect such passages
Snakepit – 50% of being poisonous; HD 1, Atk 1 bite (1-4)

As examples of what these tables can generate, here is a three-layer dungeon made with the above charts. It’s surprising how easy these charts are to use and you can even use them at the table when the players take an unexpected turn into a monster lair. In the maps below, arrows (on the first map) indicate an exit. A ladder will be drawn with an arrow indicating UP or DOWN. Traps will be labeled beside the trap. Guaranteed wandering monsters are marked with a direction of travel. Each square is 5′ meaning single-file travel; when the corridor increases, two can stand abreast. When it decreases, one must squeeze. Give them a penalty on attacks, can’t use 2-handed swords, etc.