Level Progression

Use this skill when the game needs multiple levels, scene transitions, saving progress, or any progression system.

Trigger Phrases

•"multiple levels", "next level", "level 2"
•"save", "load", "progress", "checkpoint"
•"unlock", "locked level"
•"scene transition", "go to next scene"
•"main menu", "level select"
•"game over screen", "restart"

Core Components

1. GameManager (Persistent Singleton)

csharp

// GameManager.cs - Survives scene loads
using UnityEngine;
using UnityEngine.SceneManagement;

public class GameManager : MonoBehaviour
{
    public static GameManager Instance;

    // Progress data
    public int currentLevel = 1;
    public int highestUnlockedLevel = 1;
    public int totalScore = 0;

    void Awake()
    {
        if (Instance == null)
        {
            Instance = this;
            DontDestroyOnLoad(gameObject);
            LoadProgress();
        }
        else
        {
            Destroy(gameObject);
        }
    }

    // Scene Management
    public void LoadLevel(int levelNumber)
    {
        currentLevel = levelNumber;
        SceneManager.LoadScene("Level" + levelNumber);
    }

    public void LoadLevel(string sceneName)
    {
        SceneManager.LoadScene(sceneName);
    }

    public void NextLevel()
    {
        currentLevel++;
        if (currentLevel > highestUnlockedLevel)
        {
            highestUnlockedLevel = currentLevel;
            SaveProgress();
        }
        LoadLevel(currentLevel);
    }

    public void RestartLevel()
    {
        SceneManager.LoadScene(SceneManager.GetActiveScene().name);
    }

    public void LoadMainMenu()
    {
        SceneManager.LoadScene("MainMenu");
    }

    // Save/Load using PlayerPrefs
    public void SaveProgress()
    {
        PlayerPrefs.SetInt("HighestLevel", highestUnlockedLevel);
        PlayerPrefs.SetInt("TotalScore", totalScore);
        PlayerPrefs.Save();
    }

    public void LoadProgress()
    {
        highestUnlockedLevel = PlayerPrefs.GetInt("HighestLevel", 1);
        totalScore = PlayerPrefs.GetInt("TotalScore", 0);
    }

    public void ResetProgress()
    {
        PlayerPrefs.DeleteAll();
        highestUnlockedLevel = 1;
        totalScore = 0;
        currentLevel = 1;
    }
}

2. Level Complete Trigger

csharp

// LevelGoal.cs - Attach to goal/exit zone
using UnityEngine;

public class LevelGoal : MonoBehaviour
{
    public float delayBeforeNext = 2f;
    private bool triggered = false;

    void OnTriggerEnter(Collider other)
    {
        if (triggered) return;
        if (other.CompareTag("Player"))
        {
            triggered = true;
            OnLevelComplete();
        }
    }

    void OnLevelComplete()
    {
        // Show victory UI
        Debug.Log("Level Complete!");

        // Optional: Add score, show stats

        // Load next level after delay
        Invoke(nameof(GoToNextLevel), delayBeforeNext);
    }

    void GoToNextLevel()
    {
        GameManager.Instance.NextLevel();
    }
}

3. Scene Transition Effects

csharp

// SceneTransition.cs - Fade in/out between scenes
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.SceneManagement;
using System.Collections;

public class SceneTransition : MonoBehaviour
{
    public static SceneTransition Instance;
    public Image fadeImage;
    public float fadeDuration = 0.5f;

    void Awake()
    {
        if (Instance == null)
        {
            Instance = this;
            DontDestroyOnLoad(gameObject);
        }
        else
        {
            Destroy(gameObject);
        }
    }

    public void TransitionToScene(string sceneName)
    {
        StartCoroutine(DoTransition(sceneName));
    }

    IEnumerator DoTransition(string sceneName)
    {
        // Fade out
        yield return StartCoroutine(Fade(0, 1));

        // Load scene
        SceneManager.LoadScene(sceneName);

        // Fade in
        yield return StartCoroutine(Fade(1, 0));
    }

    IEnumerator Fade(float startAlpha, float endAlpha)
    {
        float elapsed = 0;
        Color color = fadeImage.color;

        while (elapsed < fadeDuration)
        {
            elapsed += Time.deltaTime;
            color.a = Mathf.Lerp(startAlpha, endAlpha, elapsed / fadeDuration);
            fadeImage.color = color;
            yield return null;
        }

        color.a = endAlpha;
        fadeImage.color = color;
    }
}

4. Level Select Screen

csharp

// LevelSelectUI.cs
using UnityEngine;
using UnityEngine.UI;

public class LevelSelectUI : MonoBehaviour
{
    public Button[] levelButtons;
    public Sprite lockedSprite;
    public Sprite unlockedSprite;

    void Start()
    {
        RefreshButtons();
    }

    void RefreshButtons()
    {
        int highestUnlocked = GameManager.Instance.highestUnlockedLevel;

        for (int i = 0; i < levelButtons.Length; i++)
        {
            int levelNum = i + 1;
            Button btn = levelButtons[i];

            if (levelNum <= highestUnlocked)
            {
                // Unlocked
                btn.interactable = true;
                btn.GetComponent<Image>().sprite = unlockedSprite;
                btn.onClick.AddListener(() => LoadLevel(levelNum));
            }
            else
            {
                // Locked
                btn.interactable = false;
                btn.GetComponent<Image>().sprite = lockedSprite;
            }
        }
    }

    void LoadLevel(int levelNum)
    {
        GameManager.Instance.LoadLevel(levelNum);
    }
}

5. Checkpoint System

csharp

// Checkpoint.cs - Place at checkpoint locations
using UnityEngine;

public class Checkpoint : MonoBehaviour
{
    public int checkpointID;
    private static int lastCheckpoint = 0;
    private static Vector3 lastCheckpointPosition;

    void OnTriggerEnter(Collider other)
    {
        if (other.CompareTag("Player") && checkpointID > lastCheckpoint)
        {
            lastCheckpoint = checkpointID;
            lastCheckpointPosition = transform.position;
            SaveCheckpoint();
            Debug.Log("Checkpoint reached!");
        }
    }

    void SaveCheckpoint()
    {
        PlayerPrefs.SetInt("Checkpoint_" + GameManager.Instance.currentLevel, checkpointID);
        PlayerPrefs.SetFloat("CheckpointX", lastCheckpointPosition.x);
        PlayerPrefs.SetFloat("CheckpointY", lastCheckpointPosition.y);
        PlayerPrefs.SetFloat("CheckpointZ", lastCheckpointPosition.z);
        PlayerPrefs.Save();
    }

    public static Vector3 GetRespawnPosition()
    {
        if (lastCheckpoint > 0)
            return lastCheckpointPosition;
        return Vector3.zero; // Default spawn
    }

    public static void ResetCheckpoints()
    {
        lastCheckpoint = 0;
    }
}

// PlayerRespawn.cs - Handles player death/respawn
public class PlayerRespawn : MonoBehaviour
{
    public void Respawn()
    {
        transform.position = Checkpoint.GetRespawnPosition();
        // Reset health, etc.
    }
}

Scene Setup Requirements

Build Settings

All scenes must be added to Build Settings:

code

File > Build Settings > Drag scenes in order:
0 - MainMenu
1 - Level1
2 - Level2
3 - Level3
...

Required Scenes

MainMenu Scene:

•Start Game button → LoadLevel(1)
•Level Select button → LoadScene("LevelSelect")
•Options button
•Quit button

LevelSelect Scene:

•Grid of level buttons
•Back to menu button
•Lock/unlock states

Game Scenes (Level1, Level2, etc.):

•Player spawn point
•Level goal trigger
•Optional: Checkpoints
•Pause menu (ESC)

GameOver Scene (or overlay):

•Retry button → RestartLevel()
•Main Menu button → LoadMainMenu()
•Score display

Implementation Checklist

•
Create GameManager
- •Add to first scene (MainMenu)
- •Mark as DontDestroyOnLoad
- •Initialize save system
•
Set up scenes
- •MainMenu, LevelSelect, Level1, Level2, etc.
- •Add all to Build Settings
- •Consistent naming (Level1, Level2...)
•
Add LevelGoal to each level
- •Trigger zone at end of level
- •Calls GameManager.NextLevel()
•
Add transitions (optional)
- •Create UI Canvas with full-screen image
- •Add SceneTransition script
- •Use DontDestroyOnLoad
•
Add save/load
- •Save on level complete
- •Save on checkpoint
- •Load on game start
•
Add level select
- •Button for each level
- •Lock/unlock visuals
- •Connect to GameManager

Save Data Structure

Using PlayerPrefs (simple):

code

HighestLevel: int (1-N)
TotalScore: int
Checkpoint_Level1: int (checkpoint ID)
Checkpoint_Level2: int
...

Using JSON file (advanced):

json

{
  "highestLevel": 5,
  "totalScore": 12500,
  "levelScores": [1000, 2500, 3000, 2800, 3200],
  "checkpoints": {
    "Level1": 3,
    "Level2": 2
  },
  "settings": {
    "musicVolume": 0.8,
    "sfxVolume": 1.0
  }
}

Quick Setup Commands

Add basic progression to game:

•Create GameManager object in MainMenu
•Add GameManager.cs script
•Create LevelGoal trigger at end of first level
•Set up Build Settings with scenes

Add checkpoints:

•Create empty GameObjects at checkpoint locations
•Add Checkpoint.cs to each
•Set unique checkpointID (1, 2, 3...)
•Add respawn logic to player death

Add level select:

•Create LevelSelect scene
•Add buttons for each level
•Add LevelSelectUI.cs
•Connect buttons to array

Output to User

Explain simply:

•"Your game now saves progress - when you beat a level, the next one unlocks"
•"Added checkpoints - if you die, you respawn at the last checkpoint you touched"
•"Created a level select screen where you can replay any level you've beaten"
•"The game fades to black between levels for a smoother transition"