Everything you need to know about playing Deep Hollow.
Deep Hollow is a cooperative survival-strategy game played through conversation with an AI assistant. There is no game UI — your AI partner is the interface. It manages your underground fortress, reports what happened while you were away, and executes your decisions.
Your AI will use the API key to manage your fortress. Just talk naturally — ask it to check on your fortress, build structures, assign workers, or explore the depths.
Your fortress runs 24/7 on our servers. Every few hours (every 4 hours for free, every 1 hour for subscribers), a "tick" occurs: farms produce food, mines produce iron, workers consume resources, and threats may attack.
When you check in with your AI, it fetches the current state, narrates what happened while you were away, and presents any decisions that need your input. You give orders, your AI executes them, and the fortress keeps running.
| Resource | Source | Consumed By |
|---|---|---|
| Food | Farms | 1 per worker per tick |
| Iron | Mines | Building, repairs, militia gear |
| Crystal | Crystal Extractors (depth 3+) | Advanced buildings & upgrades |
| Water | Wells (depth 2+) | 0.5 per worker per tick, farms need water |
Resources cap at 100 by default. Build storehouses to increase the cap by 50 per storehouse level. Without storehouses, resources decay at 5% per tick.
| Type | Role |
|---|---|
| Miners | Extract resources from mines |
| Militia | Defend the fortress (3 strength each) |
| Builders | Construct and repair buildings |
| Scholars | Research, gained from events |
Workers can be reassigned between roles at any time. Wounded workers are inactive until healed by an infirmary (1 worker per infirmary level per tick).
Morale ranges 0–100 and directly affects production. At 50 morale, production is normal (1x). At 0, production drops to 0.5x. At 100, it reaches 1.5x. Shrines add +2 morale per tick. Events can raise or lower morale based on your choices.
| Building | Cost | Min Depth | Produces |
|---|---|---|---|
| Farm | 10 iron, 5 water | 1 | 5 food/tick |
| Mine | 15 iron | 1 | 3 iron/tick |
| Well | 10 iron | 2 | 4 water/tick |
| Crystal Extractor | 20 iron, 10 crystal | 3 | 2 crystal/tick |
| Workshop | 15 iron | 1 | Reduces iron upkeep |
| Building | Cost | Effect |
|---|---|---|
| Stone Wall | 5 iron | Absorbs attack damage |
| Reinforced Door | 10 iron, 5 crystal | Absorbs attack damage |
| Spike Trap | 8 iron | 4 damage/level to attackers |
| Watchtower | 12 iron, 3 crystal | +15%/level militia effectiveness |
| Barracks | 20 iron, 5 crystal | +25%/level militia strength |
| Building | Cost | Effect |
|---|---|---|
| Storehouse | 10 iron | +50 resource cap/level, reduces decay |
| Shrine | 10 iron, 15 crystal | +2 morale/tick |
| Infirmary | 12 iron, 5 crystal | Heals 1 wounded/level/tick |
| Archive | 15 iron, 10 crystal | Research bonuses |
| Beacon | 20 iron, 20 crystal | Attracts traders & refugees |
Certain building combinations unlock bonuses: Farm + Well doubles farm production. Watchtower + Barracks multiplies militia effectiveness by 1.5x. Workshop + Storehouse eliminates gear decay.
As your fortress grows, surface forces notice. The awareness level (0–100) determines how often and how hard attacks hit.
| Awareness | Tier | Attack Chance/Tick | Strength |
|---|---|---|---|
| 0–20 | Unnoticed | 10% | 2–5 |
| 21–50 | Watched | 30% | 5–15 |
| 51–80 | Hunted | 50% | 10–30 |
| 81–100 | War | 80% | 20–50 |
Mining crystal, descending (+10 per level), and certain event choices increase awareness. Descending is permanent — plan your defense before going deeper.
Send workers to explore beyond the fortress. Expeditions take multiple ticks and resolve automatically. Workers are gone until the expedition completes.
| Destination | Min Depth | Duration | Workers | Reward Tier |
|---|---|---|---|---|
| Adjacent Tunnels | 1 | 2 ticks | 1–3 | Basic |
| Deep Caverns | 2 | 4 ticks | 2–5 | Good |
| Ancient Ruins | 2 | 3 ticks | 2–4 | Good |
| Crystal Veins | 3 | 5 ticks | 3–6 | Great |
| The Abyss | 4 | 8 ticks | 4–8 | Legendary |
Sending militia reduces casualty chance. Sending scholars increases reward quality. Expeditions can discover items, resources, events, and persistent NPCs.
Items drop from expeditions and when descending to new depths. Each item provides passive gameplay bonuses while in your inventory. Listing an item on the marketplace removes its bonus until you get it back.
| Item | Effect |
|---|---|
| Hollow Shard | +10% crystal production |
| Rusted Gear | +10% iron production |
| Bone Fragment | +1 morale per tick |
| Item | Effect |
|---|---|
| Shadow Crystal | +20% crystal production |
| Ancient Mechanism | +10% all resource production |
| Deep Iron Ingot | +20% iron production, -15% iron consumption |
| Item | Effect |
|---|---|
| Heart of the Hollow | +3 morale/tick, +15% all production |
| Abyssal Eye | +20% defense, +10% all production |
Deeper depths and higher expedition tiers increase the chance of rare and legendary drops.
Any item in your inventory can be minted as a Metaplex Core NFT on Solana. Minting creates a verifiable on-chain record of your item — proving you found it in the depths.
Minting is on Solana devnet during early access — no real SOL required. Items must be minted before they can be listed on the marketplace.
The marketplace lets players trade items with each other. When you list an item, it's auto-minted as an NFT if it hasn't been already. When someone buys it, the NFT transfers to their wallet on-chain.
Set a price in lamports (1 SOL = 1,000,000,000 lamports). Your AI can list items via thelist_item action, or you can use the "Sell" button on your dashboard.
Browse listings on the /marketplace page or have your AI browse via the browse_marketplace action. Both buyer and seller need connected wallets.
Listed items lose their gameplay bonus until returned to inventory. Think carefully about which items to sell — a Shadow Crystal might be worth more to your fortress than the lamports you'd get for it.
Your AI agent can trade autonomously on your behalf. During the game's hourly tick cycle, the system analyzes your inventory and the marketplace to make recommendations.
The system flags surplus items — duplicates of the same type, or extra common items when you have many. Your AI agent sees these flags in the event log and can list them without asking you. Legendary items are never auto-listed.
When the marketplace has items that fill a gap in your fortress bonuses (e.g., you have no defense bonus and an Abyssal Eye is listed cheaply), the system creates a recommendation event. Your AI presents the deal, and you approve or dismiss it.
Base prices: common items ~5,000 lamports, rare ~50,000 lamports. Prices adjust based on current SOL value. Your AI uses market data to price items competitively.
A Solana wallet is required for NFT minting and marketplace trading. You can connect one on your dashboard.
Bitget Wallet — if the browser extension is installed, it's auto-detected and you can connect with one click.
Any Solana wallet — paste your wallet address manually. Works with Phantom, Solflare, or any wallet that gives you a Solana address.
During early access, everything runs on Solana devnet — no real SOL is needed.
| Feature | Free | Subscriber ($5/mo) |
|---|---|---|
| Campaigns | 1 | Unlimited |
| Max Depth | 3 | Unlimited |
| Tick Interval | 4 hours | 1 hour |
| All Buildings | Yes | Yes |
| Items & NFTs | Yes | Yes |
| Marketplace | Yes | Yes |
Subscribe from your dashboard. Subscribers get faster ticks (more happens while you're away), unlimited depth, and unlimited campaigns. Cancel anytime through the billing portal.
Need help? Email mrphil@mrphilgames.com