The Tunnel Codex
The Tunnel Codex is a narrated video series that introduces the game's mechanics in short, focused episodes. Each video is approximately 1-1.5 minutes long, narrated by the NPC character Old Gravel.
These videos complement the written documentation. For detailed reference information, see the corresponding documentation sections linked below.
Episodes
Welcome to the Depths
Game overview — exploration, combat, POIs, day/night/week cycle, bosses
Introduces the core gameplay loop: tile-by-tile exploration on seeded maps, auto-battle combat, points of interest, the Day/Night cycle with movement budgets, and the 3-week boss progression.
Know Your Mole
Player stats (HP, ATK, ARM, SPD, DIG), gear slots, progression
Covers the 5 player stats and how they affect gameplay. Explains gear slots, starting loadout, and how defeating bosses unlocks additional equipment capacity.
What Lurks Below
Field enemies, their traits, tiers, and night movement
Introduces the 12 field enemy archetypes, the 3-tier system, gold rewards, and how enemy behavior changes during Night phases when creatures move toward the player.
The Bosses Await
Boss encounters, weaknesses, phases, and weekly progression
Covers all boss encounters across Week 1, Week 2, and Week 3, their weakness tags, unique trait mechanics, and how boss difficulty scales across acts.
The Art of the Swing
Combat system — auto-battle, speed advantage, strikes, damage
Deep dive into the auto-battle combat system: turn order, SPD advantage, damage resolution, strike cap, on-hit trigger rules, and stalemate prevention.
Status of the Underground
Status effects — Chill, Rust, Bleed, Shrapnel, Exposed, Wounded
Explains all four status effects (Chill, Shrapnel, Rust, Bleed), their mechanics, stacking behavior, and the trigger keywords used across items and enemies.
Tools of the Trade
Tools, item tags, item sets, fusing, upgrades, and build identity
Covers the item system: 8 tags, Tool vs Gear distinction, the 80-item catalog, rarity tiers, item upgrading through fusion, and itemset synergies.
Treasures in the Dark
POIs — caches, shops, forges, fast travel, rest
Guide to all 14 Point of Interest types: where to find items, upgrade gear, heal, fast travel, and strategically shape your build during a run.
Beyond the Tunnel
Game modes — Gauntlet, Duels, Pit Draft
Overview of the PvP modes: Gauntlet endurance runs with Echo opponents, seed-matched Duels, and instant Pit Draft deckbuilding.
Marks of a Mole
Quests, skins, and NFT items
Upcoming episode covering the quest system, cosmetic skins, and NFT item integration. Requires game design spec completion.