Behind the Scenes: BlokAIsia AI City Builder

A behind-the-scenes look at the solo-developer vibe-coding, game design and storytelling process which went into creating BlokAIsia, the AI City Builder.

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This is a behind-the-scenes look at BlokAIsia, the AI city builder. For the main game submission entry, please refer to https://devpost.com/software/blokaisia.

Tools used: Freepik, FAL fal.ai, Google Cloud, ElevenLabs, Bolt

  • Freepik: Seedream image generation API
  • fal.ai: 3D model generation API (Trellis)
  • Google Cloud: Gemini 2.5 Flash, Gemini 2.5 Image Generation, Firebase, Cloud Functions, Firestore, Cloud Storage, Google AI Studio
  • ElevenLabs: text to speech voiceover, music generation
  • Bolt.new: vibe coding, UI prototyping

Inspiration

BlokAIsia is inspired by my liking for city builder games like Tropico and Cities Skylines, and my desire to showcase how modern AI tools can create entirely new forms of gameplay and player freedom which were previously not possible, instead of being a gimmick.

By integrating genAI into the classic city builder for tasks like asset creation and interesting core gameplay mechanics, rather than gimmicky additions with little value-add, we make limitless creative expression accessible to every player.

As a solo developer trying to make a city builder game in three weeks, with all the systems that go into one, the AI tools provided during the Chroma Awards were critical in expediting every stage of the workflow - from asset creation to prototyping and modular integration.

What it does

BlokAIsia is a next-generation city-building simulation where players co-create their dream city with the power of generative AI.

At its core, BlokAIsia has a nuanced city simulation engine with 3D graphics and assets generated by using image-to-3D model Trellis hosted on fal.ai and Google Gemini Image Generation, and thoughtful AI-enhanced gameplay mechanics like custom public relations campaigns with real consequences for your city's citizens.

Design any building you want with genAI

If you can imagine it, you can put it in your city - BlokAIsia includes a fully self-contained 3D asset editor which uses Google Gemini Image Generation to generate concept art based on user prompts and Trellis 3D running on fal.ai to generate 3D models based on user preferences. The buildings can be put into play with custom parameters like pollution, number of residents, manufacturing output and more.

Custom media campaigns - emergent storytelling

Influence your citizens - create custom billboards which directly influence your citizens' mood, goods consumption and more using Freepik Image Generation APIs. Write your own story to control or encourage your citizens.

Nuanced city simulation

BlokAIsia is built on a solid city simulation base, with systems to simulate finance, employment, supply chains, pollution and overall city happiness, allowing for deep gameplay. Initial simulations and UI were built using bolt.new and Gemini 2.5 Pro in AI Studio.

Original voice lines and soundtrack

BlokAIsia's radio announcer spices up your gameplay with hilarious commentary and a tasteful soundtrack, all generated using ElevenLabs.

How we built it

The magical text-to-3D workflow is powered by Google's Gemini Image Generation for the initial 2D concept quadrants, followed by fal.ai's API for Trellis 3D model to create the 3D mesh. The entire process is managed and optimized on the backend by Google Cloud, using Firebase Functions to optimize the GLB files by up to 80% and Firestore and Storage to manage the asset database.

The media campaign system uses the Freepik Image Generation API (Seedream model) to generate billboard art, while the "populace's" reaction is intelligently simulated by a prompt sent to Google Cloud's Gemini 2.5 Flash, which returns nuanced gameplay effects for emergent storytelling, instead of being just another gimmick. The fantastic radio voiceover was brought to life using ElevenLabs.

The game is rendered in-browser using Babylon.js. My development was massively accelerated by indispensable tools - as a solo developer, these tools were critical to completing the project on time; we prototyped the UI with incredible speed using Bolt.new, while Google AI Studio was our constant co-pilot. Gemini's ability to autonomously search Babylon.js documentation was a lifesaver for tackling complex graphics problems like the custom mountain mega-shaders.

Challenges we ran into

Developing a project of this ambition within a tight timeframe presented several significant hurdles.

  • The Three-Week Marathon: The entire project, from concept to a functional demo, was completed in just under three weeks, as a solo developer. Juggling this intense development cycle with existing work and school commitments was a huge challenge.
  • Designing the Simulation: Architecting a complete city simulation system in such a short period was a monumental task. Balancing the economy, citizen needs, and the impact of AI-generated elements required rapid iteration and UI design, made possible by Gemini and bolt.new.

Accomplishments that we're proud of

  • In-game 3D asset creator: We successfully designed and implemented a complete text-to-3D asset pipeline inside a city-builder. This empowers players to be creators without leaving the game, a giant leap forward for the genre
  • Delivering a Cohesive Vision: Despite the time crunch, we created a playable prototype that demonstrates multiple deeply integrated AI features working in harmony to deliver real gameplay effects and emergent storytelling instead of gimmicks

What we learned

  • Importance of Powerful Dev Tools: with powerful developer tools like bolt.new and powerful LLMs like Google Gemini 2.5 Pro, tasks like prototyping the game UI and simulation and even parts of the game design process can be done in minutes instead of days. For a solo developer, this is a gigantic force multiplier, which even made completing the game in just 3 weeks possible in the first place; without which it would be impossible as city builders are immensely complex machines with many parts.

What's next for BlokAIsia - AI City Builder

  • Performance improvements and game balance - the city simulation can be further optimized to run well for medium-to-large size cities.
  • More emergent AI gameplay - more generative AI features, such as AI-generated quests, unique citizen dialogue that references the player's custom buildings, and even procedural map generation from a simple description. The default map is already partially AI-generated using Gemini Image Generation!

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