The title "IMPSTR" represents the players. The letter 'O' has been eliminated from the game, and we are highlighting 'M' because it is the imposter.

A modern, offline-first social deduction game for Android built with Material Design 3

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📑 Table of Contents

• 📖 Overview
• ✨ Key Features
• 🎯 How to Play
• 🎨 Design System
• 🧱 Architecture

Build Requirements

• JDK 17: This project uses Gradle toolchains and requires JDK 17 for builds.
• Android Studio Koala (2024.1.1) or newer is recommended.
• 🧠 State Management System
• 🚀 Getting Started
• 🏗️ Build & Testing
• 📝 License & Developer

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📖 Overview

IMPSTR is an intensely strategic, pass-and-play social deduction game designed specifically for Android. Taking inspiration from party classics like Mafia and Among Us, IMPSTR streamlines the experience into a seamless, high-polish mobile app.

Through a beautifully crafted Material Design 3 interface, 3 to 10 players share a single device. Everyone receives a secret word—except the IMPSTR. In the new Stealth Mode, the IMPSTR isn't just told they are the imposter; they receive a decoy word to help them blend in. It's a battle of wits: Crewmates must identify the IMPSTR without giving the word away, while the IMPSTR must play it cool to survive the vote!

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✨ Key Features

Feature	Description
🎭 Stealth Mode (New)	Imposters receive a decoy word instead of an explicit "IMPOSTER" label, creating deeper bluffing opportunities.
🎮 Pass-and-Play	Play together in the same room using just one device. Supports 3–10 players.
🔒 Fully Offline	No internet required. Play anywhere without ads or tracking.
🎨 Material Design 3 Engine	Powered by Jetpack Compose with fluid spring physics and dynamic theming.
📂 Rich Word Library	24+ word categories randomly generated for high replayability.
🛠️ Unified Design System	Centralized tokens for consistent spacing, animations, and corner radii.
🛡️ Encrypted State	Data is securely persisted via Android's EncryptedSharedPreferences.

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🎯 How to Play

Flowchart of a Standard Match

graph TD;
    A[Lobby Setup] -->|Start Round| B[Pass-and-Play Role Reveal];
    B -->|Everyone Knows Role| C[Timed Discussion Phase];
    C -->|Timer Ends / Skip| D[Host Conducts Voting];
    D --> E[Elimination Results];
    E -->|Win Conditions Met?| F{Check Winner};
    F -- Yes --> G[Final Results Screen];
    F -- No --> C;

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Game Phases Detailed

1. Setup Phase

• Customize player names and the total count of IMPSTRs.
• Choose between Normal Mode (explicit roles) and Stealth Mode (decoy word system).

2. Pass & Reveal Phase

• Pass the phone; each player flips an animated card.
• In Normal Mode, you see the secret word or "IMPOSTER".
• In Stealth Mode, you see either the Secret Word (Crewmate) or a Decoy Word (IMPSTR).

3. Discussion Phase

• A tense 3-minute timer begins. Talk to figure out who doesn't know the word.
• Tip: If you're the IMPSTR, use your decoy word to find common context with the crewmates!

4. Voting & Results Phase

• The Host selects suspects. Eliminated roles are unmasked.
• Play repeats until one side claims victory.

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🎨 Design System

IMPSTR uses a centralized Token-based Design System (DesignSystem.kt) to ensure visual excellence:

• Consistent Geometry: All buttons use MD3 medium shapes (16dp), and bottom bars use specific 28dp top anchors.
• Expressive Motion: Spring physics (DampingRatioMediumBouncy) power every interaction.
• Semantic Colors: Custom color tokens (ImposterRed, CrewmateGreen) ensure tactical clarity.

Note

For a deep dive into the UX philosophy, see our Design Overview.

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🧱 Architecture

IMPSTR leverages a robust Model-View-ViewModel (MVVM) pattern with Unidirectional Data Flow (UDF).

• UI Layer: Passive Jetpack Compose screens observer the GameState.
• ViewModel Layer: Houses the central MutableStateFlow<GameState>. Manages the game machine, timers, and voting logic.
• Data Layer: Clean repository pattern for encrypted storage and word pair generation (Stealth Mode).

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🚀 Getting Started

Prerequisites

• Android Studio Ladybug (or higher)
• JDK 17 integration
• Minimum API Level 31 (Android 12) targeting API 36.

Build via CLI

./gradlew assembleDebug
adb install -r app/build/outputs/apk/debug/app-debug.apk

Build for Release (R8 Enabled)

./gradlew assembleRelease

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🏗️ Build & Testing

We maintain a robust testing suite for win conditions and stealth logic.

./gradlew testDebugUnitTest

Unit Test Highlights:

Test Class	Coverage
GameViewModelTest	Boundaries, role assignment, win evaluation, and Stealth Mode word pairs.

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📝 License & Developer

Created and Maintained with 💙 by Surajit Das
Licensed under the GNU General Public License v3.0. Copyright © 2026 Surajit Das.

Trust no one. Have fun! 🎭