Most people think building an AR mobile game needs a dev team, months of work, and expertise in 3D math or SDKs. Graphic designer Ruth Heasman just disproved that. In one week, using Replit Agent, she designed, built, and shipped Spookseek AR, a fully working iOS ghost-hunting game<\/p>\n\n\n\n
It leverages the phone’s camera, accelerometer, gyroscope, and haptics, landing on TestFlight for Replit’s mobile Buildathon.<\/p>\n\n\n\n
Heasman started clueless, with no computer science background, embracing ignorance as her edge. Replit Agent hooked her instantly: “Now I’m in.” In a year, she built 20+ apps, hit the top 0.1% of Replit builders, and earned master status, proving non-coders can ship fast.<\/p>\n\n\n\n
In this article, we will break down exactly how Heasman built Spookseek AR, the technical decisions she made, the problems she hit, how she used Replit Agent to work through them, and what the whole experience teaches about what is actually possible when a non-developer with strong taste and a real deadline decides to ship something ambitious.<\/p>\n\n\n\n
TL;DR<\/strong><\/p>\n\n\n\n Spookseek AR <\/a>is an augmented reality ghost hunting game. Players move around their real space with the phone, scanning the room and tracking ghosts that float around them. Captured ghosts appear in a bestiary as holographic-style cards, complete with playful visuals that feel more inviting than frightening.<\/p>\n\n\n\n The game uses the phone’s camera, accelerometer, gyroscope, and haptics together, making it something that genuinely belongs on a phone rather than on any other device. That was intentional. Heasman set herself a design constraint from the start to use as many hardware features as possible and build something that could only exist as a mobile experience.<\/p>\n\n\n\n The standard approach for an iOS AR game is to use Apple’s ARKit, which handles the heavy lifting of mapping the physical environment and placing virtual objects in it. Most iOS AR games lean on Apple’s ARKit. In this Buildathon, that path was blocked. Expo would not allow ARKit in the flow she needed, but she still had to ship a working build to TestFlight.<\/p>\n\n\n\n Rather than scaling back her idea to fit within easier constraints, Heasman used Replit Agent to design a different solution entirely. The result was a custom lightweight 3D <\/a>system built from scratch, not borrowed from an existing AR framework, but designed specifically for what Spookseek AR needed.<\/p>\n\n\n\n She picked Three.js for rendering ghosts on a virtual sphere around the player. This simulates spirits floating in physical space. She tuned fields of view, angles, and camera math for fair aiming, not random or frustrating. Custom Fresnel-style shaders made ghosts translucent, glowing, and convincingly ethereal.<\/p>\n\n\n\n Instead of ARKit’s room mapping, she built a conceptual sphere centered on the player. Ghosts sit at positions on this sphere. Gyroscope and accelerometer data track which part the camera views. Pointing at a ghost’s spot makes it appear like it’s floating in your room, without true spatial mapping.<\/p>\n\n\n\n She tasked Replit Agent with a bespoke 3D system: “Build me an entirely custom setup.” Early issues had models “sticking to screen sides,” breaking targeting. These math quirks trip up non-devs, but Heasman iterated through them, pushing past where most would quit.<\/p>\n\n\n\n If there is one technical lesson in Heasman’s story that applies to every developer, not just non-coders, it is the gap between development and production builds. The hardest problems only showed up when she moved from the dev app to the production build. The dev app was “very forgiving” and ran more slowly. <\/p>\n\n\n\n The production version on the phone ran much faster, and subtle timing issues caused things to fail without visible errors. She describes that middle stretch of the build as a “chasm” where the dev version worked and the production version “didn’t work at all.”<\/p>\n\n\n\n This is a real phenomenon in mobile development that catches even experienced developers. The development environment adds layers of tooling that slow execution slightly, which can mask timing-sensitive bugs. <\/p>\n\n\n\n When you remove those layers in a production build, the code runs at full speed, and those timing issues surface as hard-to-diagnose failures. For Heasman, navigating this without formal training in mobile debugging was the most demanding part of the week.<\/p>\n\n\n\n Like many builders, she discovered that the last 20% of polish takes at least half the time. Getting both dev and production behaving well and getting a smooth TestFlight build turned out to be the real test. <\/p>\n\n\n\n This is worth internalizing, whether you are a non-coder using Replit Agent or a professional developer with years of experience. The first version that technically works is rarely the version that ships cleanly.<\/p>\n\n\n\n Heasman’s background as a graphic designer shaped Spookseek AR as much as the engineering decisions did. She was deliberate about the tone from the beginning. She went through multiple iterations of ghost designs. Early ghosts looked more realistic and “a bit severe.<\/p>\n\n\n\n “That wasn’t the vibe she wanted. Spookseek AR needed to feel like “a fun ghost hunt, not too serious, not too heavy.” After several passes, she landed on the current batch of friendlier, more playful ghosts.<\/p>\n\n\n\n The bestiary, the collection screen where captured ghosts are displayed, reflects her love of bold visual design. The cards have a holographic feel and treat each ghost like a unique character rather than a generic asset. As she puts it, the graphic design side of the work “is just joy.”<\/p>\n\n\n\n Sound design received the same level of attention. She used tools like Suno and ElevenLabs <\/a>to generate voices and audio moments, adding music and character lines so the experience felt alive even in quiet domestic spaces. These layers of audio and interaction are what separate a technically working app from one that people actually want to keep playing.<\/p>\n\n\n\n Heasman’s experience with Spookseek AR is a practical demonstration of several things that are easy to say but hard to actually believe until you see them done.<\/p>\n\n\n\n\n
What Is Spookseek AR?<\/strong><\/h2>\n\n\n\n
It is an iOS augmented reality ghost hunting game built by a designer in one week using Replit Agent<\/strong><\/h3>\n\n\n\n
Why She Chose an Ambitious AR Idea<\/strong><\/h2>\n\n\n\n
\n
The Technical Problem: No ARKit in Expo<\/strong><\/h2>\n\n\n\n
How She Built a Custom 3D System With Agent<\/strong><\/h2>\n\n\n\n
Step 1: Choose Three.js and Build Ghost Rendering<\/strong><\/h3>\n\n\n\n
Step 2: Create the Virtual Sphere Workaround<\/strong><\/h3>\n\n\n\n
Step 3: Overcome 3D Positioning Challenges with Agent<\/strong><\/h3>\n\n\n\n
The Hardest Part: Dev Build vs. Production Build<\/strong><\/h2>\n\n\n\n
1. The Dev-Production Chasm<\/strong><\/h3>\n\n\n\n
2. Why Timing Bugs Emerge in Production<\/strong><\/h3>\n\n\n\n
3. The Polish That Makes It Ship<\/strong><\/h3>\n\n\n\n
How Agent Helped Her Through the Hardest Moments<\/strong><\/h2>\n\n\n\n
\n
The Design Work: Making Ghosts Feel Fun, Not Scary<\/strong><\/h2>\n\n\n\n
1. Crafting Playful Ghost Designs<\/strong><\/h3>\n\n\n\n
2. Layering Audio for Immersive Fun<\/strong><\/h3>\n\n\n\n
\n Ruth Heasman<\/strong>, with zero computer science training, outpaced AAA game teams<\/strong> by shipping Spookseek AR<\/strong> solo in just one week<\/strong>. Leveraging Replit Agent<\/strong> for bespoke 3D engineering<\/strong>, she built an AR experience while her husband works on multi-year titles<\/strong> with hundreds of developers.\n
\n Her virtual sphere hack<\/strong> delivered AR functionality without relying on ARKit<\/strong>, proving that AI tools democratize complex mobile development<\/strong>\u2014especially for designers.\n<\/div>\n\n\n\nPrivacy and User Experience as Product Principles<\/strong><\/h2>\n\n\n\n
\n
What Other Builders Can Learn<\/strong><\/h2>\n\n\n\n
\n