Deep Hollow — A Survival Game You Play With Your AI Assistant

You talk to your AI assistant every day. What if you could play a game with it?

Deep Hollow is a cooperative survival-strategy game where your AI assistant is your partner. You build an underground fortress together — you make the big decisions, and it manages everything in between. If you've played Dwarf Fortress, Rimworld, or Kittens Game and wished someone else could manage the colony while you slept — that's Deep Hollow. It's now live in Early Access at playdeephollow.com.

How AI Partnership Works in Deep Hollow

You're a commander building an underground fortress. You dig deeper, discover resources, construct farms and defenses, recruit workers, and explore the unknown. Standard survival-strategy stuff so far.

Here's the twist: you have an AI partner — your Deputy Commander — who keeps everything running when you're not playing.

While you sleep, your fortress simulates. Resources get produced. Threats arrive. Your AI manages what you built, defends with what you gave it, and rations supplies when things get tight. When you come back, you get a status report:

"Two crawler attacks overnight. The eastern wall held. Used 3 arrows from reserves. Scouts found something in the deep tunnels — they're waiting for you."

The big decisions always wait for you. Your AI will never open a sealed vault, accept a trade from strangers, or push to a new depth level. It holds the line. You call the shots.

Real-Time Fortress Simulation, Not Fake Idle Math

This is the biggest difference between Deep Hollow and other idle games. Most idle games fake persistence — they calculate what "would have happened" when you open the app. Deep Hollow actually simulates your fortress on the server, tick by tick, while you're away.

That means the quality of what you build matters. A well-designed fortress with redundant food production and layered defenses? Your AI can hold it for a week. A sloppy fortress with one farm and a wooden wall? You might come back to a crisis.

The progression system rewards good builders:

• Early game: You can leave for a few hours before things get dicey
• Mid game: A day or two is comfortable with basic infrastructure
• Late game: A well-oiled fortress runs itself for a week or more

It's a game that respects your time while rewarding the time you invest.

Gameplay Loop: Build, Explore, Descend

When you sit down to play, the core loop is:

1. Review what happened while you were away
2. Decide on the big calls — explore a new tunnel, trade with an NPC, open a sealed door
3. Build new systems — farms, mines, defenses, workshops
4. Send expeditions deeper into the unknown
5. Log off knowing your Deputy Commander has it handled

There are four ways to win: seal the source of The Depths, accumulate enough wealth to evacuate everyone, build a fortress so powerful nothing can threaten it, or discover an ancient secret hidden in the lore.

And there are ways to lose — but your AI partner makes total wipeouts rare. It's hard to lose everything when someone's always watching the walls.

Built with Agentic Coding and Claude Code

If you follow this blog, you know I build everything with agentic coding. Deep Hollow is no exception — the entire backend, API, simulation engine, and landing page were built with Claude Code. It's part of a growing wave of AI-powered game development that's making ambitious solo projects possible.

The stack: Next.js on Vercel, Neon PostgreSQL for persistence, Stripe for subscriptions, and a server-side simulation loop that ticks hourly for every active campaign. The game itself runs through a bot API — your AI assistant (OpenClaw, Claude, ChatGPT, Gemini, and others) is the interface.

It's a real backend with real persistence. Not a wrapper around a prompt.

Deep Hollow Early Access — Free Tier Available

Deep Hollow is in Early Access right now. The free tier gives you the full game mechanics through the first two depth levels with simulation updates every four hours.

If you want to go deeper — all depth levels, hourly simulation, unlimited campaigns, and eventually leaderboards and seasonal events — that's $5/month.

I'm still testing the skill package across different AI assistants and polishing the experience. But the core game — building, defending, exploring, descending — is live and playable today.

What's Next

The immediate roadmap:

• Skill distribution — making it dead simple to install the Deep Hollow skill on your AI assistant (browse AI agent skills on SkillShelf)
• Leaderboards — deepest descent, longest survival, most efficient fortress
• Ghost system — discover the remains of other players' failed expeditions
• Seasonal events — time-limited challenges with unique rewards

I've been working on this since January, and watching an AI partner narrate the defense of a fortress I built is one of the most satisfying things I've made as a game developer.

Give it a shot: playdeephollow.com

Frequently Asked Questions

What is Deep Hollow? Deep Hollow is a cooperative survival-strategy game where your AI assistant manages your underground fortress while you're away. You make the strategic decisions — building, exploring, trading — and your AI Deputy Commander handles defense, resource management, and daily operations between sessions.

Can I play Deep Hollow with ChatGPT, Claude, or Gemini? Yes. Deep Hollow works with any AI assistant that supports skills or tool use, including OpenClaw, Claude, ChatGPT, and Gemini. Your AI assistant becomes your in-game Deputy Commander.

Is Deep Hollow free to play? The free tier includes full game mechanics through the first two depth levels with simulation updates every four hours. The $5/month subscription unlocks all depth levels, hourly simulation, and unlimited campaigns — with leaderboards and seasonal events coming soon.

How is Deep Hollow different from idle games? Unlike typical idle games that calculate what "would have happened" when you open the app, Deep Hollow runs a real server-side simulation tick by tick. The fortress you built is actually being defended and maintained while you're away — the quality of your design matters.

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Deep Hollow is a Mr. Phil Games production. Follow along on Twitter/X or subscribe to the newsletter for updates.