🐧🕵‍♂️Pengu's Nightshift: How I created a Horror Version of Pokémon GO using KIRO

Introduction: What is Pengu's Night Shift?

Pengu’s Night Shift is inspired by Pokémon GO — specifically the real-world geolocation movement and the feeling of exploring your surroundings with a purpose.

But it isn’t a Pokémon GO clone. The similarity ends at “you walk around in the real world.”

The core gameplay loop is completely different: instead of collecting creatures, you’re using analog tools, gathering evidence, and deducing which ghost you’re dealing with.

If you’re familiar with these titles, the easiest way to describe it is:
Pengu’s Night Shift sits somewhere between Pokémon GO and Phasmophobia (but in real life).

Here is a screenshot from the game.

Inspiration & Story

When I was a kid growing up in Indonesia, my school had a reputation. Everyone said the fourth floor was haunted - the hallways were always dark, the lights flickered, and nobody wanted to go up there after class. Looking back now, I'm pretty sure the teachers intentionally started those rumors just so kids wouldn’t go up there.

So naturally... My friends and I got curious.

We downloaded those old "ghost radar" apps on our tiny phone and treated them like real paranormal detectors. We would roam through empty classrooms, peek into pitch black hallways, and scare ourselves half to death because as an eight year old kid, I fully believed those EMF spikes meant a ghost was behind me.

*I think it looked something like this. *

These moments are unforgettable. It made our imagination run wild. It felt like an adventure.

That memory stuck with me for years.

So for Kiroween, I wanted to bring that childhood feeling back - but this time:

• with real detection tools
• with an actual deduction system
• with mechanics that build tension

I also originally wanted to revive Clippy (Microsoft's old dekstop companion) as my "Ressurection" angle - turning him into a paranormal investigation assistant.

But due to IP restrictions, I had to pivot.

So instead, I revived the concept of classic 90s desktop helpers and redesigned it as:

Pengu, A little mascot who reacts to your tools, gives hints, and adds charm without risking disqualification. One of my scrapped ideas was to use a magnifying glass character — basically Clippy’s cousin — but I didn’t want to get too close to the original design.

Another subtle inspiration came from Pokemon GO - the feeling of: -exploring the real world -walking toward something on a radar -using your phone as a window into a hidden layer of reality

My game isn't AR but it captures that same energy of "something is out there, go find it."

Just like how Pokemon GO turned everyday streets into adventure zones, my game let me turn my ghost hunting childhood memories into interactive again and built with real mechanics instead of fake ghost radar apps.

Whos is Pengu?

Pengu is this guy. Pengu is the little assistant that guides you through investigations. He is your boss. If he has tips for you, listen to him.

What it does

Pengu's Night Shift is a mobile first (PWA) investigation game that turns real world locations into haunted "hotspots." Players would walk around outside with their phone, use analog inspired tools to hunt for a hidden ghost, and then try to deduce which ghost they are dealing with before sanity runs out.

The core gameplay pattern is divided into two parts. Which are overworld exploration and investigation mode. However, current MVP is restricted by admin mode's movement for easier testing for the judges. No GPS implementation yet for movement.

Overworld Exploration: This is the bread and butter Pokémon Go style exploration. The main view of the game is a map which will follow the users' location. Instead of catching Pokémon, players will collect camera rolls, boosts, charms and field journals that will help your investigations. However, the GPS system has yet to be implemented. So we have to click on map to move for current testing. Although it does take real world lat,lng calculations.

Investigation Mode: This gameplay loop is activated when someone is within the Investigation hotspots and starts the mission. The map turns into a full screen ghost hunting device kits. Movements is simulated through devmode.

The tools:

• Radar: Direction Only Point toward the ghost's hidden spot. It doesn't tell you what the ghost is, or how close, just a general direction. The movements are simulated on devmode for the judges but this is used as if your phone is the compass, as it would move according to where you point your phone
• EMF: Distance Only Shows how close you are to the ghost (0-5)

• Camera: Core Evidence Tool You line up a shot and take a photo. The camera then "develops" and locks the camera for 7 seconds, forcing you to swap to other tools while you wait. When it finishes, you may see a faint silhoutte, moution blur, shadow figure, glitch streaks or nothing at all. You have to face the ghost to take a photo or you will capture nothing.

• Spirit Box: Talk to them and get their personality traits A dual knob interface where you tune two knobs until the frequencies "lock in" the ghot's signal. When locked, you get to ask it one of three questions. They will either ignore or respond based on their trait.

• Thermal:A quick temperature check that tells you if the area feels Normal, Cold Spot, or Deep Cold – useful in combination with other tools, but never a solo solve.

All of this feeds into an Evidence Screen where the player reviews:

• Photos they’ve taken
• Spirit Box responses
• Rough thermal readings

From there, they make a final guess from a roster of seven ghosts (Wraith, Shade, Poltergeist, Banshee, Phantom, Onyx, Trickster). Each has a unique combination of:

• EMF personality
• Spirit Box behavior
• Word pool
• Camera manifestation
• Thermal profile All information about them is stored in the codex.

This creates variety of strategies and skills to solve each investigation.

The Seven Entities

I think I had the most fun designing the ghost mechanics and how they interacted with the tools. But I wish I had more time to develop more of their personality within the game and how they interacted with tools as well as a deeper story in the codex, as well as field journals.

I think the one **I had the most fun creating was Trickster - The Mimic. **This Entity has the most personality and makes the Investigations difficult

Each ghost in Pengu's Nightshift has a unique personality, behavioral pattern, and investigation profile. Here's what you need to know before entering the field:

1. Wraith - The Drifter

Threat Level: HIGH | Difficulty: EASIEST

Profile:
The Wraith is your introduction to paranormal investigation—fast-moving, elusive, but relatively predictable. It leaves barely a trace, making it difficult to photograph but easier to identify through its consistent behavioral patterns.

Behavioral Signature:

• EMF Pattern: Calm and steady readings, barely flickering even when close
• Spirit Box: Aggressive response rate (70-80%), but words are soft and melancholic
• Camera: Faint silhouettes (80% chance) or completely invisible (20%)
• Thermal: Normal ambient temperature—no cold anomalies
• Personality: Passive observer, non-threatening despite high speed

Spirit Box Signature Words:

• Unique: "lost soul," "thin veil," "drifting by"
• Personality (Aggressive): "your fear," "leave now," "watching you," "always here"

Investigation Notes:
The Wraith is the ghost you'll encounter first, and it teaches you the fundamentals. Its calm EMF signature contrasts with its aggressive Spirit Box responses, showing you that evidence must be combined—no single tool tells the whole story. The faint silhouettes in photos are your primary confirmation.

Field Report Extract:

"The readings were steady, almost too steady. When I finally got close enough to take a photo, I could barely make out a shape. Just a faint outline, like smoke caught in the flash... I got out before my sanity broke. Some of us aren't so lucky." — K. Morrison, March 15th, 2019

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2. Shade - The Hidden One

Threat Level: MEDIUM | Difficulty: EASY

Profile:
The Shade is a shy entity that actively avoids detection. It won't reveal itself until you're uncomfortably close, making it a test of patience and nerve. Its reluctance to be seen is both its defining trait and its weakness.

Behavioral Signature:

• EMF Pattern: Shy—readings stay low until you're very close, then spike suddenly
• Spirit Box: Shy response rate (30-40%), requires precise tuning
• Camera: Half-formed body (70%) or faint silhouette (30%)
• Thermal: Normal temperature
• Personality: Elusive, prefers to remain hidden, non-aggressive

Spirit Box Signature Words:

• Unique: "still quiet," "deep corner," "watching softly"
• Personality (Shy): "quiet please," "go away," "far away," "hiding now," "don't know"

Investigation Notes:
The Shade teaches you patience. You'll spend more time searching than with any other ghost. Your EMF meter will frustrate you with low readings, and the Spirit Box requires careful, precise tuning. When you finally photograph it, the half-formed body in the image is unmistakable—caught between worlds, trying to hide even from the camera.

Field Report Extract:

"It took me hours to find it. I had to get uncomfortably close before the readings spiked... When I finally photographed it, the image showed a half-formed body. Not quite solid, not quite transparent. Like it was caught between worlds, trying to hide even from the camera." — T. Chen, July 3rd, 2020

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3. Poltergeist - The Chaos Bringer

Threat Level: HIGH | Difficulty: MEDIUM

Profile:
The Poltergeist is pure chaos. Erratic movement, unstable readings, and aggressive behavior toward equipment make it one of the most frustrating entities to investigate. Nothing about it follows a pattern—and that IS the pattern.

Behavioral Signature:

• EMF Pattern: Unstable—readings spike and drop randomly (2→5→1→4)
• Spirit Box: Chaotic response rate (50-60%), unpredictable timing
• Camera: Motion blur (75%) or glitch streaks (25%)
• Thermal: Cold spots appear and disappear suddenly
• Personality: Aggressive, chaotic, enjoys disrupting equipment

Spirit Box Signature Words:

• Unique: "mess maker," "inside walls," "here-here" (glitched double)
• Personality (Chaotic): "break things," "make noise," "play now," "everywhere now," "moving fast"

Investigation Notes:
The Poltergeist will test your ability to work under pressure. Your EMF meter becomes unreliable, cold spots vanish before you can confirm them, and photos come out as pure motion blur. The key is recognizing the chaos itself as evidence. When nothing makes sense, you're dealing with a Poltergeist.

Field Report Extract:

"The EMF meter went haywire. One second it was at 2, the next it spiked to 5, then dropped to 1. I couldn't get a stable reading... Equipment started malfunctioning. My flashlight flickered. The EMF meter's display glitched. I got out before it could do worse." — R. Patel, November 22nd, 2018

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4. Banshee - The Screaming Fury

Threat Level: EXTREME | Difficulty: HARD

Profile:
The Banshee is driven by intense emotion—rage, sorrow, and anguish compressed into a single entity. It's aggressive, announces its presence from a distance, and its manifestations are psychologically devastating. This is not an entity you investigate casually.

Behavioral Signature:

• EMF Pattern: Aggressive—spikes even at distance, announces presence
• Spirit Box: Shy response rate (30-40%), but requires perfect tuning
• Camera: Screaming face (85%) or deep shadow (15%)
• Thermal: Cold spots, temperature drops rapidly
• Personality: Extremely aggressive, emotionally overwhelming

Spirit Box Signature Words:

• Unique: "mourning song," "doorway edge," "still listening"
• Personality (Shy): "quiet please," "go away," "in shadows," "hiding now," "stay back"

Investigation Notes:
The Banshee is a psychological threat. The screaming face in photographs has traumatized multiple investigators. The Spirit Box requires both knobs tuned perfectly, and when you hear "anger, sorrow, leave," you should listen. The aggressive EMF spikes from a distance are your warning—this entity wants you to know it's there.

Field Report Extract:

"When I took the photo, I saw its face. A screaming, anguished face frozen in the flash. The image burned into my mind. I can still see it when I close my eyes... I ran. I'm not ashamed to admit it. Some entities you don't investigate—you survive them." — M. O'Brien, October 31st, 2017

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5. Phantom - The Void Walker

Threat Level: HIGH | Difficulty: HARD

Profile:
The Phantom is uncanny. It refuses to be photographed, brings extreme cold, and has a calm but deeply unsettling presence. Its voice through the Spirit Box is described as "wrong," "inhuman," and "empty." This entity exists in a space between presence and absence.

Behavioral Signature:

• EMF Pattern: Calm—steady readings, almost peaceful
• Spirit Box: Chaotic response rate (50-60%), voice sounds reversed or distorted
• Camera: Invisible (95%) or faint glitch (5%)
• Thermal: Deep cold—temperatures drop below freezing
• Personality: Calm but unsettling, refuses to be seen

Spirit Box Signature Words:

• Unique: "empty echo," "between worlds," "fading in"
• Personality (Chaotic): "break things," "hear me," "nowhere close," "circling you," "shift now"

Investigation Notes:
The Phantom is identified by what it doesn't do. Photos come back blank. The extreme cold (below 0°C) is your primary evidence, combined with the calm EMF signature. Investigators report taking 7-10 photos before catching even a faint glitch. The psychological impact of feeling its presence while seeing nothing is profound.

Field Report Extract:

"I took seven photos. Seven. Every single one came back blank. Just the empty room, as if nothing was there. But I could feel it. The weight of its presence was suffocating... On my eighth photo, I caught a faint glitch in the corner. Just a flicker. Proof it was there, refusing to be seen." — L. Kowalski, January 8th, 2021

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6. Onyx - The Riftwalker

Threat Level: EXTREME | Difficulty: HARD

Profile:
Onyx is not a shadowy, passive entity—it is a corpse-thin hunter, a creature that looks like it stepped out of a forgotten rift in the world. Its ribcage is violently torn open, exposing a glowing cavity that pulses like a dying star. Long, blood-soaked claws scrape across floors and leave streaks behind.

Witnesses describe it as "a humanoid silhouette stretched too far, eyes burning like coals, moving wrong—like every bone bends where it shouldn't."

It does not hide underground. It does not stalk slowly. It appears, suddenly and violently, as if reality blurred for a moment.

Behavioral Signature:

• EMF Pattern: Aggressive—fast spikes from 1→5 even at medium distance, feels like it's "already too close"
• Spirit Box: Low, ragged breathing layered under a deep-frequency growl, response rate 70-80% (aggressive personality), tuning locks feel "unstable" as if the frequency is fighting you
• Camera: Distorted humanoid with glowing chest cavity (80%) or full apparition with bloody claws and red eyes (20%), photos often show motion blur even when it's standing still
• Thermal: Deep cold—temperature drops several degrees instantly, cold trail streaks follow its movement
• Personality: Predatory, territorial, violent—doesn't toy with you, it approaches. Fast.

Spirit Box Signature Words:

• Unique: "hunger bleeds," "open chest," "red eyes watching"
• Personality (Aggressive): "tear you," "your blood," "closer," "it hurts," "run now"

Investigation Notes:
Onyx is the most visually horrifying ghost in the roster. EMF spikes suddenly, often fooling players into thinking the ghost teleported closer. Indicators include scratch marks appearing in the environment, heavy breathing in Spirit Box, camera distortions that look like shredded film, and unusually long shadows on the ground.

Players who get a photo of the glowing chest cavity or red eyes will know instantly they're dealing with something not human.

Field Report Extract:

"I heard claws before I saw anything. Slow dragging, like something testing the floor. The EMF jumped from 1 to 5 in a heartbeat. When my camera developed the photo, the thing's chest was ripped open—glowing, empty. It wasn't a shadow. It wasn't a shape. It was looking at me." — S. Nakamura, April 17th, 2019

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7. Trickster - The Deceiver

Threat Level: HIGH | Difficulty: HARDEST

Profile:
The Trickster is the ultimate challenge. It shows contradictory evidence, oscillating EMF patterns, drifting Spirit Box signals, and unpredictable behavior. It's playful, mischievous, and enjoys manipulating investigators. Identifying it requires recognizing that nothing makes sense—and that's the point.

Behavioral Signature:

• EMF Pattern: Mischievous—oscillates in perfect sine waves (too perfect)
• Spirit Box: Uses ALL word pools—contradictory messages
• Camera: Glitch streaks (70%) or motion blur (30%)
• Thermal: Cold spots appear behind you, always behind you
• Personality: Playful, deceptive, psychologically manipulative

Spirit Box Signature Words:

• Unique: "again again" (glitched repeat), "look up," "behind you"
• Personality (Contradictory): Uses ALL personality words from aggressive, shy, and chaotic pools randomly

Investigation Notes:
The Trickster is identified by contradiction. It might show aggressive EMF but shy Spirit Box responses. It uses words from all personality types, creating impossible combinations. The oscillating EMF pattern is too deliberate—it's showing you what you want to see. When evidence doesn't match any known ghost, you're dealing with the Trickster. Multiple investigators report laughing uncontrollably during encounters—not from humor, but from psychological breakdown.

Field Report Extract:

"It was playing with me from the start. My EMF meter readings oscillated in a perfect sine wave. Up, down, up, down. Too perfect. Too deliberate... I left when I realized I was laughing. Not because anything was funny—because I was losing my mind. That's what it wanted." — D. Martinez, September 9th, 2020

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How I built it

Pengu's Night Shift was built almost entirely through Kiro's AI-powered IDE, using a methodology with a mix or "spec driven development" and "vibe coding" - where design vision and technical implementation happen in tandem through natural conversation with an AI agent.

The Kiro Workflow Instead of traditional coding where you write every line manually, I used Kiro's spec-driven development system:

Steering Documents - I created high-level design rules that guided every decision:

• 001-game-design-document.md - The core vision
• 006-analog-horror-component-system.md - Visual design system for paper/journal aesthetics
• 007-investigation-tools-design-system.md - How each ghost-hunting tool should look and feel
• 014-ghost-tool-mechanics.md - The deduction gameplay loop Specs

I broke down features into structured requirements, design docs, and task lists:

• Spec 009: Investigation UI Transformation - Converting the UI from clean digital to analog horror
• Spec 010: Unified Backpack System - Context-aware inventory that adapts between overworld and investigation modes
• Spec 013: Tool Component Refactoring - Breaking 1000+ line monolithic tool files into reusable components
• Spec 014: Ghost Data & Codex System - The encyclopedia of ghost types and their behaviors
• Spec 018: Spirit Box & EMF Redesign - Final polish on the core

investigation tools Iterative Refinement - Each spec went through multiple iterations:

The Tech Stack

• React + TypeScript - Type-safe component architecture
• Vite - Lightning-fast development builds
• Zustand - Lightweight state management for game logic
• Leaflet - Interactive maps for overworld exploration
• Framer Motion - Smooth animations and transitions
• PWA - Mobile-first, installable web app

*The Visual Evolution, Here is the full evolution of Figma. *

There are four pages you can explore on there. Current UI, Visual Inspiration, Mock Styles Created by AI, Mock Style Reworked UI.

One of the most dramatic transformations was the analog horror aesthetic. I started with clean, modern UI and evolved it into something that feels like authentic 1980s paranormal investigation equipment:

*Before: Clean digital interfaces with flat colors *

After:
Aged paper textures with coffee stains and burn marks Polaroid-style photos with tape and pins Heavy steel casings with rust, scratches, and wear CRT screen effects with scanlines and phosphor glow Handwritten notes (Caveat font) mixed with typewriter text (Courier New) 10-15+ damage elements per device for authenticity This was achieved through a component-based design system where I built reusable "LEGO pieces":

• Aged paper foundation - Coffee stains, burns, blood smears - Instant camera aesthetic - Crooked masking tape - Authentic scrawled notes The Investigation Tools Each tool went through extensive iteration to feel physically real.

From:

To:

All created using Kiro. This is CSS by the way, not AI art. I was so surprised.

Challenges I ran into

• The biggest challenge was codebase complexity. As the project grew, messy naming conventions and duplicate files (for example having both EMFMeterMock.tsx in my UI playground and EMFTool.tsx in production) caused Kiro sometimes update the wrong files or create duplicates instead of modifying existing components.
• Getting the visuals to the way I want it in my head was very DIFFICULT. I had to go through so many different versions of the UI and many many prompts later finally getting the result I had envisioned in my head.

• Fun challenge I ran into: since it was my first type developing a game, gameplay balancing and iterative play test was a fun challenge I ran into. Developing lore, world building through journals was really fun.

Accomplishments that I am proud of

This is the first game I have ever built fully with AI, and I'm incredibly proud of how it turned out. I pushed Kiro to its limit, refining the systems over and over until it matched the vision I had in my head. Different iterations, even making CSS art look like a game engine fully made by Kiro. Visually and gameplay wise. The coolest part? I genuinely had fun playing my own game and that feeling made all the hardwork worth it.

I think the thing that I am proud the most is being able to have an idea that is ambitious enough and use a tool that is powerful enough to make my limitless ideas come to life just created within in two weeks (but I did spent like most of my days working on this).

This is the evolution of my Investigation Tools.

What I learned

I learned that AI assisted development is very powerful and I believe that it is the future for fast prototyping and even engineering. As long as you have the vision, and the guidance you can create anything. However, it is important to maintain developer discipline. For future reference, I would focus a lot on cleaning as I go. This means refactoring regularly, maintaining clear naming conventions, deleting old prototypes, and being explicit when giving instructions.

The key insight for me personally is that AI doesn't replace software engineering principles, it amplifies them. Good project structure and regular cleanup are even MORE important when working with AI, not less. You still need to think like a developer and maintain architecture, even when the AI handles the implementation.

Working with Kiro felt like being a project lead directing a highly skilled engineering team — except everything happened at 100× speed. I focused on vision and mechanics, and Kiro handled the execution.

My last take away is that AI does not replace an engineer's problem solving skills, as there were times where I ran into bugs and got stuck at a loop. But using my problem solving skills as a developer, I was able to guide it to solve the problem at a highlevel while they dig dive into the implementation.

What's next for Pengu's Night Shift.

This MVP is a prototype of my full idea. It is just the beginning. Now that core investigation loop is working, the next steps focus on bringing that childhood feeling of adventure, creating unforgettable memories through our imaginations.

Planned features include:

• Implementing full Augmented Reality GPS feature. Not just using Devmode.
• Currency, Level Tracking implementation. Unlockable ghosts per level.
• Moving ghosts with signature pathing. Therefore checking radar and EMF is a must.
• Tool upgrades through the shops, this makes grinding to get money rewarding to get better gear
• With better gear, the ghosts will get more and more complex.
• Provocation system. We can place salts, and other items to make the ghost angry. Results to different patterns of behaviors, maybe more aggression, etc.
• More ghost types, perhaps 20+ with overlapping behaviors
• New tools because there's more ghosts
• Multiple ghosts in one investigation??
• Multiplayer system where multiple people can do the same investigation. Requires consistent ghost tracking with actual lat, lng positioning
• In game purchasable things with real money

I hope you enjoyed reading this as much I enjoyed making this project. Cheers!