The Mission

Welcome to our next GDG Monthly Coding Jam, powered by Google’s Antigravity and Nano Banana!

This month, we’re going video-game-themed with Fossil Hunter: Chrono Dig, a guided game-building code-along inspired by and in collaboration with San Antonio ACM’s VelociCode hackathon.

Instead of starting from a blank screen, we’ll walk through a structured starter project together and build a playable grid-based excavation puzzle game. Players will dig through tiles, uncover fossils, avoid hazards, and use time-based mechanics to complete each level.

The goal is simple: learn by building, experiment with agentic development using Google’s Antigravity, and leave with a real mini-game you can keep customizing after the event.

What is a Build Jam?

Our Build Jam format is fast, focused, and beginner-friendly. The goal is to open the starter kit, follow the code-along, understand the core mechanics, and ship something real before the night is over.

This is not a traditional hackathon where you have to figure everything out alone. We’ll go step by step through the same core concept together:

• Set up the starter project

• Understand the game board

• Build the tile reveal mechanic

• Add fossil discovery logic

• Add hazards and scoring

• Explore time-inspired puzzle mechanics

• Use AI w/ Googles Antigravity, Nano Banano, and Gemini to help with game assets, logic, and creative polish

Bring your laptop, your power brick, and your best fossil-hunting energy.

The Game Concept

Fossil Hunter: Chrono Dig is a grid-based excavation puzzle game where each tile may hide a fossil, hazard, clue, or empty dig site.

Players must make strategic choices about where to dig while managing risk, score, and time. The “chrono” twist gives us room to experiment with time-based mechanics like limited turns, time bonuses, rewind ideas, or special dig tools.

Think archaeology meets puzzle strategy meets agentic game development.

Agentic Game Development with Google’s Antigravity

This session is designed to explore how agentic development can support the game development process using Google’s Antigravity.

We’ll look at how tools like Antigravity, Gemini, and Nano Banana can help with:

• Brainstorming game mechanics

• Generating asset ideas

• Creating fossil, tile, and character concepts

• Improving code structure

• Debugging game logic

• Rapidly prototyping features

The focus is not just on using AI to generate code. The focus is on learning how to guide agentic tools while still understanding the system we are building.

Starter Repo Coming Soon

The Fossil Hunter: Chrono Dig starter repo and code-along materials are currently being finalized and will be shared before the event.

Keep an eye on the GDG San Antonio GitHub organization for the starter project, setup instructions, and guided build steps:

https://github.com/GDG-SAN-ANTONIO

Updates will also be posted on the Coding Jam site as we get closer to the event. You can RSVP now, and the build kit will be available soon.

The Pre-Flight Checklist

To get the most out of the code-along, please try to have these ready before you arrive:

• Install Antigravity: We’ll use Antigravity as part of the agentic development workflow.

• GitHub Account + Git Installed: The starter kit will be hosted as a GitHub repo, and you’ll clone it during setup once it is available.

• Google Account: You’ll need this to access Google AI tools and generate a Gemini API key if needed.

• Laptop + Charger: This is a hands-on build night, so bring a device you can code on.

Drop-ins are still welcome, even if you do not have everything installed yet.

Parking Made Simple

• City Tower Parking Garage: $10 max for the day, right next door.

• St. Mary’s Parking Garage: $10 max for the day, one block away.

• Street Parking: Free city street parking after 6:00 PM.

Who is this event for?

Everyone!

Whether you’re a developer, designer, student, game-curious builder, or just someone who wants to see what agentic development with Google’s Antigravity looks like in practice, you belong here.

Come by, say hello, and build with us.

📅 Date: Friday, July 24, 2026
⏰ Time: 6:00 PM – 8:15 PM CDT
📍 Location: Geekdom 3rd Floor | 110 East Houston Street, San Antonio, TX 78205
🎮 Format: Guided agentic game code-along
🛠️ Starter Repo: Coming soon
🔗 GitHub: https://github.com/GDG-SAN-ANTONIO