Level Design & Platforms

Welcome to the heart of 2D platformer design! In this lesson, you'll learn how to create engaging level layouts, implement various platform types, and design obstacles that challenge players while maintaining fun gameplay flow.

What You'll Learn

By the end of this lesson, you'll be able to:

• Design effective platform layouts using proven game design principles
• Implement different platform types (solid, moving, disappearing, one-way)
• Create obstacle patterns that create engaging challenges
• Use Unity's 2D tools for efficient level building
• Apply level design theory to create memorable gameplay moments

The Art of Platform Design

Great platform design is about creating a perfect balance between challenge and accessibility. Your platforms should guide players naturally through your level while presenting interesting obstacles that feel fair and rewarding to overcome.

Core Platform Design Principles

1. Visual Hierarchy

• Use color and contrast to guide player attention
• Make important platforms stand out from background elements
• Create clear visual paths through your level

2. Progressive Difficulty

• Start with simple jumps and gradually increase complexity
• Introduce new platform types one at a time
• Allow players to master each element before adding new challenges

3. Player Agency

• Provide multiple paths when possible
• Give players choices in how to approach challenges
• Avoid forcing players into single solutions

Setting Up Your Level Design Workspace

Let's start by creating a proper level design setup in Unity:

Step 1: Create a New Scene

1. Create New Scene: File → New Scene → 2D Template
2. Save Scene: Save as "Level_01" in your Scenes folder
3. Set Up Camera: Position your camera to show the full level area

Step 2: Configure Grid System

1. Enable Grid: Window → 2D → Grid and Snap Settings
2. Set Grid Size: Use 1 unit grid for consistent platform sizing
3. Enable Snap: This helps align platforms perfectly

Step 3: Create Level Boundaries

// Create invisible boundaries to prevent players from falling off
public class LevelBoundary : MonoBehaviour
{
    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.CompareTag("Player"))
        {
            // Respawn player or restart level
            other.transform.position = GameManager.Instance.GetLastCheckpoint();
        }
    }
}

Platform Types and Implementation

Let's implement the essential platform types that every 2D platformer needs:

1. Solid Platforms (The Foundation)

Basic Solid Platform Setup:

1. Create Platform GameObject

   • Add Sprite Renderer with your platform sprite
   • Add Box Collider 2D
   • Set Collider as "Platform" layer

2. Platform Script for Basic Functionality:

public class Platform : MonoBehaviour
{
    [Header("Platform Properties")]
    public bool isSolid = true;
    public bool canPassThrough = false;

    void Start()
    {
        // Set up platform behavior based on type
        if (canPassThrough)
        {
            GetComponent<Collider2D>().isTrigger = true;
        }
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.CompareTag("Player") && canPassThrough)
        {
            // Allow player to pass through from below
            StartCoroutine(TemporarilyDisableCollision(other));
        }
    }

    IEnumerator TemporarilyDisableCollision(Collider2D playerCollider)
    {
        Physics2D.IgnoreCollision(GetComponent<Collider2D>(), playerCollider, true);
        yield return new WaitForSeconds(0.5f);
        Physics2D.IgnoreCollision(GetComponent<Collider2D>(), playerCollider, false);
    }
}

2. Moving Platforms (Dynamic Challenge)

Moving Platform Implementation:

public class MovingPlatform : MonoBehaviour
{
    [Header("Movement Settings")]
    public Transform[] waypoints;
    public float moveSpeed = 2f;
    public float waitTime = 1f;
    public bool loopMovement = true;

    private int currentWaypoint = 0;
    private bool isMoving = true;
    private Vector3 startPosition;

    void Start()
    {
        startPosition = transform.position;
        if (waypoints.Length == 0)
        {
            // Create default waypoints if none assigned
            CreateDefaultWaypoints();
        }
    }

    void Update()
    {
        if (isMoving && waypoints.Length > 0)
        {
            MoveToWaypoint();
        }
    }

    void MoveToWaypoint()
    {
        Vector3 targetPosition = waypoints[currentWaypoint].position;
        transform.position = Vector3.MoveTowards(transform.position, targetPosition, moveSpeed * Time.deltaTime);

        if (Vector3.Distance(transform.position, targetPosition) < 0.1f)
        {
            StartCoroutine(WaitAtWaypoint());
        }
    }

    IEnumerator WaitAtWaypoint()
    {
        isMoving = false;
        yield return new WaitForSeconds(waitTime);

        currentWaypoint++;
        if (currentWaypoint >= waypoints.Length)
        {
            if (loopMovement)
            {
                currentWaypoint = 0;
            }
            else
            {
                // Reverse direction
                System.Array.Reverse(waypoints);
                currentWaypoint = 0;
            }
        }

        isMoving = true;
    }

    void CreateDefaultWaypoints()
    {
        // Create simple back-and-forth movement
        GameObject waypoint1 = new GameObject("Waypoint1");
        GameObject waypoint2 = new GameObject("Waypoint2");

        waypoint1.transform.position = startPosition;
        waypoint2.transform.position = startPosition + Vector3.right * 5f;

        waypoints = new Transform[] { waypoint1.transform, waypoint2.transform };
    }
}

3. Disappearing Platforms (Timing Challenge)

Disappearing Platform Script:

public class DisappearingPlatform : MonoBehaviour
{
    [Header("Disappearing Settings")]
    public float disappearDelay = 1f;
    public float reappearDelay = 2f;
    public bool startVisible = true;

    private SpriteRenderer spriteRenderer;
    private Collider2D platformCollider;
    private bool isVisible = true;

    void Start()
    {
        spriteRenderer = GetComponent<SpriteRenderer>();
        platformCollider = GetComponent<Collider2D>();

        if (!startVisible)
        {
            SetPlatformVisibility(false);
        }
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.CompareTag("Player") && isVisible)
        {
            StartCoroutine(DisappearSequence());
        }
    }

    IEnumerator DisappearSequence()
    {
        // Wait for player to potentially leave platform
        yield return new WaitForSeconds(disappearDelay);

        // Disappear
        SetPlatformVisibility(false);

        // Wait before reappearing
        yield return new WaitForSeconds(reappearDelay);

        // Reappear
        SetPlatformVisibility(true);
    }

    void SetPlatformVisibility(bool visible)
    {
        isVisible = visible;
        spriteRenderer.enabled = visible;
        platformCollider.enabled = visible;
    }
}

4. One-Way Platforms (Strategic Movement)

One-Way Platform Implementation:

public class OneWayPlatform : MonoBehaviour
{
    [Header("One-Way Settings")]
    public bool allowUpwardPassage = true;
    public bool allowDownwardPassage = false;

    void OnTriggerEnter2D(Collider2D other)
    {
        if (other.CompareTag("Player"))
        {
            PlayerController player = other.GetComponent<PlayerController>();
            if (player != null)
            {
                // Check if player is coming from below
                if (player.transform.position.y < transform.position.y && allowUpwardPassage)
                {
                    // Allow passage from below
                    StartCoroutine(TemporarilyDisableCollision(other));
                }
            }
        }
    }

    IEnumerator TemporarilyDisableCollision(Collider2D playerCollider)
    {
        Physics2D.IgnoreCollision(GetComponent<Collider2D>(), playerCollider, true);
        yield return new WaitForSeconds(0.2f);
        Physics2D.IgnoreCollision(GetComponent<Collider2D>(), playerCollider, false);
    }
}

Level Design Patterns

Now let's explore proven level design patterns that create engaging gameplay:

1. The "Breadcrumb Trail" Pattern

Concept: Guide players through your level using visual cues and platform placement.

Implementation:

• Place platforms in a clear path
• Use collectibles or visual elements to guide attention
• Create natural flow from left to right (or your chosen direction)

Example Layout:

[Platform] → [Gap] → [Platform] → [Moving Platform] → [Platform]
     ↑           ↑           ↑              ↑            ↑
  Start      Challenge    Rest Point    Dynamic      Goal

2. The "Skill Gate" Pattern

Concept: Introduce a new mechanic, let players practice it, then combine it with previous skills.

Implementation:

1. Introduction: Simple version of new mechanic
2. Practice: Slightly more complex version
3. Integration: Combine with previous mechanics
4. Mastery: Complex challenge using all skills

3. The "Risk vs Reward" Pattern

Concept: Offer players choices between safe, slow paths and dangerous, fast paths.

Implementation:

• Safe Path: Longer, easier route with collectibles
• Risk Path: Shorter, harder route with better rewards
• Balanced Design: Both paths should feel rewarding

Creating Your First Level

Let's build a complete level using these principles:

Step 1: Plan Your Level

Level Structure:

1. Opening Section (0-20%): Introduce basic mechanics
2. Development Section (20-80%): Build complexity and introduce new elements
3. Climax Section (80-95%): Most challenging part
4. Resolution Section (95-100%): Satisfying conclusion

Step 2: Build the Opening Section

Create a Simple Platform Sequence:

1. Start Platform: Large, safe starting area
2. First Jump: Small gap to test basic jumping
3. Rest Platform: Safe landing spot
4. Second Jump: Slightly larger gap
5. Checkpoint: Save progress point

Step 3: Add Development Elements

Introduce New Mechanics:

1. Moving Platform: First moving element
2. Disappearing Platform: Timing-based challenge
3. One-Way Platform: Strategic movement requirement
4. Combination Challenge: Mix of all elements

Step 4: Create the Climax

Design the Most Challenging Section:

1. Complex Platform Sequence: Multiple moving platforms
2. Timing Challenge: Disappearing platforms with tight timing
3. Precision Jumping: Small platforms requiring accuracy
4. Multi-Mechanic Integration: All platform types working together

Pro Tips for Level Design

Visual Design Tips

1. Use Color Coding

• Green platforms: Safe, solid ground
• Red platforms: Dangerous or disappearing
• Blue platforms: Moving or special mechanics
• Yellow platforms: Collectibles or rewards

2. Create Visual Flow

• Use arrows, lights, or particle effects to guide players
• Make the intended path more visually appealing
• Use background elements to suggest movement direction

3. Establish Visual Hierarchy

• Important platforms should stand out
• Background elements should not compete with gameplay elements
• Use contrast to separate interactive elements from decoration

Gameplay Design Tips

1. The "Three Strikes" Rule

• Introduce a mechanic
• Let players practice it
• Test mastery with a challenge
• Never introduce more than one new mechanic at a time

2. Provide Multiple Solutions

• Always offer at least two ways to solve a challenge
• Reward creative thinking
• Make players feel smart for finding alternative solutions

3. Use the "Goldilocks Principle"

• Too easy = boring
• Too hard = frustrating
• Just right = engaging and rewarding

Mini Challenge: Build Your First Level

Your Task: Create a complete level section using the patterns we've discussed.

Requirements:

1. Opening Section: 3-4 platforms introducing basic jumping
2. Development Section: Include one moving platform and one disappearing platform
3. Challenge Section: Combine both mechanics in a sequence
4. Visual Polish: Add color coding and visual flow elements

Success Criteria:

• Level feels challenging but fair
• Clear visual path through the level
• Smooth difficulty progression
• All platform types working correctly

Troubleshooting Common Issues

Platform Collision Problems

Issue: Player falls through platforms or gets stuck Solution:

• Check collider settings (not set to trigger unless intended)
• Ensure proper layer assignments
• Verify physics material settings

Moving Platform Issues

Issue: Player doesn't move with platform Solution:

• Use a parent-child relationship
• Implement platform movement in FixedUpdate
• Add platform detection in player controller

Performance Optimization

Issue: Too many platforms causing frame drops Solution:

• Use object pooling for moving platforms
• Implement culling for off-screen platforms
• Optimize sprite atlases and textures

What's Next?

Congratulations! You've learned the fundamentals of level design and platform mechanics. In the next lesson, we'll add enemies and AI behavior to bring your levels to life with dynamic challenges.

Coming Up: Lesson 6 will cover:

• Creating enemy AI systems
• Implementing different enemy types
• Building collision detection and damage systems
• Designing enemy patterns that complement your platform design

Key Takeaways

• Platform design is about balance: Challenge vs. accessibility
• Visual hierarchy guides players: Use color, contrast, and flow
• Progressive difficulty: Introduce mechanics one at a time
• Multiple solutions: Always offer player choice and agency
• Pattern recognition: Use proven design patterns as your foundation

Additional Resources

• Unity 2D Platformer Tutorial
• Game Design Patterns for Platformers
• Level Design Theory and Practice

Remember to test your levels frequently and get feedback from others. Great level design comes from iteration and player testing. Share your level designs in the community and get feedback from fellow developers!

Ready to add some enemies to your platformer? Join us in the next lesson where we'll create AI-driven challenges that will test your players' skills!