## 1. Project Overview

- **Project Name**: Spot the Difference

- **Type**: Casual Puzzle Game

- **Target Users**: Players who enjoy puzzles, challenges to reaction time, and observation skills

- **Platform**: Android, pure Java, English version, available on Google Play

- **Core Gameplay**: In an N×N grid, all grids display the same image. A different image is randomly inserted. Players must find the different image within a time limit to pass the level.

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## 2. Core Gameplay

1. Each level displays N×N grids.

2. Each grid displays the same image by default. One or more grids are randomly selected to display different images.

3. Player clicks on different grids:

- Correct: Mark the grid, adding to progress

- Incorrect: Deduct time or add to error count

4. Find all different grids within the time limit → Pass the level

Timeout or exceeding the error limit → Game over

5. Difficulty and Levels:

- Higher difficulty: Larger number of grids (e.g., 3×3 → 6×6 → 10×10), more different images, shorter time limit

6. The game supports timing, scoring, and leaderboard functions

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## 3. Page Design and Functions

### 3.1 Startup Page / Main Menu

- **Elements**:

- Game Logo

- Buttons: Start Game, Level Selection, Achievements, Leaderboard, Settings, Help

- **Functions**:

- Click "Start Game" to enter the default level or the last unfinished level

- Click "Level Selection" to enter the level map

- Click "Achievements" to view unlock status

- Click "Leaderboard" to view global/friend rankings

- Click "Settings" to adjust game parameters

- Click "Help" to view game rules

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### 3.2 Level Selection Page

- **Elements**:

- Level List (paginated or scrollable)

- Each level displays grid size, number of different grids, and whether it is unlocked

- **Functions**: - Click on a level to start the challenge

- Unlocked levels will be displayed as locked

- Display historical completion scores (time, number of errors, score)

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### 3.3 Game Main Interface

- **Elements**:

- N×N grid area, each grid displays an image

- Countdown timer

- Number of found / Total number of different grids

- Pause button

- Hint button (limited uses)

- **Functions**:

- Click on a different grid → Highlight the marker

- Incorrect click → Deduct time or record the number of errors

- Countdown ends → Failure

- Find all different grids → Successfully complete the level

- Hint button → Temporarily highlight the position of a different grid

- Supports landscape or portrait mode adaptation

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### 3.4 Achievement System Page

- **Example Achievements**:

- "Beginner": Complete the first level

- "Fast Hand": Complete a level within 10 seconds

- "Zero Errors": No errors in a level

- "High Difficulty Challenge": Complete the highest difficulty level

- **Features**:

- Displays unlocked and locked achievements

- Click on an achievement to view a detailed description

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### 3.5 Leaderboard Page

- **Categories**:

- Global Leaderboard

- Friends Leaderboard

- This Week/Historical Leaderboard

- **Display Information**:

- Player Nickname/Avatar

- Completion Time, Number of Errors, Score

- **Features**:

- Leaderboard Refresh (Daily or Weekly)

- Supports switching between different categories

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### 3.6 Settings Page

- **Features**:

- Sound Effects On/Off

- Background Music On/Off

- Hint Count Default Setting

- Game Difficulty Default Setting

- Language Switch (Chinese/English)

- **Features**:

- Save User Settings to Local Storage

- Load Settings the Next Time the Application Launches

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### 3.7 Help Page

- **Content**:

- Game Rules Explanation

- Operation Method

- Achievements and Rewards Explanation

- Difficulty Description