Set up your 2D game world

Make a flying obstacle prefab

Random obstacle size, direction, and speed

Steer the player

Add a scoring system

Restart the game with a bang

 Optional bonus features

Build and publish to web

In this tutorial, you'll preview the finished version of Sprite Flight: a simple, 2D arcade game where you steer a triangular ship to dodge flying obstacles. Then, you'll create a new Unity project using Unity’s 2D template and set up the basic play area for your 2D game, complete with walls around the edges of the screen. 

Overview

Create a new 2D project

Set up your layout

Navigate around a new 2D scene

Add an Obstacle sprite

Change the size and background of the camera

Create the first screen border

Duplicate to make other screen borders

Lock the aspect ratio and adjust borders

Organize the Hierarchy window and Assets folder

Optional: More things to try

Next steps

Configure the scenes in the build

Switch to the Web platform

Build your project

Publish to Unity Play 

Test your game

Optional: More things to try 

Share your project [SUBMISSION STEP]

 Your next steps 

In this course, you’ll build a 2D game in Unity — starting from a completely blank project with no assets provided, you’ll create the entire game from start to finish. In the game, you fly a simple triangle-shaped ship using mouse clicks (or screen taps on mobile). Your goal: stay alive for as long as you can by dodging flying obstacles while your score increases over time.

Along the way, you’ll learn the fundamentals of working in 2D, from navigating the Scene view to coding simple gameplay interactions. You’ll also explore key Unity systems like a user interface (UI), particle effects, audio, and publishing. By the end, you’ll not only have a complete, playable game, but you’ll also have the skills to start building your own original 2D projects.

2D Beginner Game: Sprite Flight

e0c1318e-7858-5a70-a685-7c69058d5755:EJWbNZ6QA41b2p9CvJ7MGg

sfx-MusicEthereal.ogg

sfx-Explosion.ogg

sfx-Thruster.ogg

Change your entire game concept

Swap out your sprites

Create a cohesive color scheme

Increase difficulty over time

Destroy the borders on game over

Add sound effects and background music

Add ambient background particles

Animated booster graphic with audio

Make your game compatible with mobile

Organize and manage assets in a Unity project.

Asset Management

Ellen Flaherty

Senior Learning Architect - Unity

Identify the defaults elements in a new scene, Create and manipulate GameObjects and configure their components.

Scene Building Essentials

NealEdu

Product Manager at Unity

Create simple particle systems to add dynamic environmental and gameplay effects to your scenes.

Beginner Particles and Visual Effects

ElizabethMidgley

1.1 - Course overview.mp4

8.2 - Change your entire game concept.mp4

8.5 - Increase difficulty over time.mp4

8.6 - Destroy the borders on game over.mp4

8.7 - Add sound effects and background music.mp4

8.8 - Add ambient background particles.mp4

Take your project to the next level with optional bonus features.

Gaming

Navigate to the Asset Store from the Unity Editor.

Search and filter a search in the Asset Store.

Import an asset from the Asset Store automatically via a Unity account.

Navigate to the Asset Store in a web browser.

Import an asset downloaded from the Asset Store in a web browser.

Explain the relationship between the Assets folder in the Project window and the Asset folder in file explorer.

4.1 Navigate to the Asset Store from the Unity Editor.

4.2 Search and filter a search in the Asset Store.

4.3 Import an asset from the Asset Store automatically via a Unity account.

4.4 Navigate to the Asset Store in a web browser.

4.5 Import an asset downloaded from the Asset Store in a web browser.

4.6 Explain the relationship between the Assets folder in the Project window and the Asset folder in file explorer.

Obtain assets from the Unity Asset Store

Create and assign a Material

Change the Sprite Tint color

Control the appearance of GameObjects

Veronica Brown

 Implement basic physics for GameObjects 

Apply RigidBody or RigidBody 2D components in order to enable GameObjects to act under the control of physics

Modify the basic properties of a RigidBody or RigidBody 2D component in order to control how the GameObject is affected by physics, including its mass, its drag, and the Scene's gravity

Add a collider to a GameObject and understand its function

Create and configure a Physic Material to add physical properties to a GameObject

Employ basic physics for GameObjects

Set up a new Particle System in the scene

Play, pause, stop, and restart a particle system in Scene view by using the Particle Effect window

Create a single burst of particles, rather than a continuous emission over time by using the Bursts section of the Emission module

Explain how individual Particle Systems can be combined to create more complex effects

Locate the Main module of a Particle System

Recall the three modules enabled by default in a Particle System: Emission, Shape, and Renderer

Configure a Particle System's main properties, such as lifetime, size, and max particles by modifying the Main module

Control the location and initial direction of particles by modifying the Shape module

Control the rate and timing of particles by modifying the Emission module

Control the appearance of individual particles by modifying the Renderer module

Add randomness to a Particle System by using the Random Between Two Constants feature

Change the color of a particle over its lifetime by using the gradient editor and the Color Over Lifetime module

Change the size of a particle over its lifetime by using the curve editor in the Size Over Lifetime module

Produce environmental and burst effects by configuring Unity's Particle System object

In this optional tutorial, you’ll find a collection of bonus features you can add to your 2D Sprite Flight project. These features are your opportunity to personalize your game, explore new creative directions, and push your Unity skills further.

The features below are grouped in an order that reflects how you might logically approach expanding or polishing your game — from conceptual changes to visual polish, difficulty balancing, and platform support.

You can see most of the features below highlighted in this demo version of the game on Unity Play. You can also watch this video showcasing that demo game:

You can choose to add none, some, or all of these features — or even come up with completely new ideas of your own! 

If you like your game just the way it is and don’t want to add anything else, just scroll down to the bottom of this tutorial, mark it as complete, and move on to the final tutorial where you’ll build and share your game.

Note: These steps won’t include the same level of step-by-step guidance or screenshots as earlier tutorials. They're meant to be more open-ended and challenging. Don’t be afraid to do some research, revisit earlier tutorials, or use an LLM (like Unity Muse or ChatGPT) to help figure things out — for example, try pasting in your script and asking how to implement a new feature.

At this point, you’ve built a solid game system — a player-controlled, triangle-shaped ship that must dodge flying asteroid-type obstacles. But what if your game was about something totally different?

By changing just the visuals and theme, you can completely transform your game’s identity. Since your characters and obstacles are made from simple shapes, it’s easy to reimagine them into something new: a mouse escaping hungry cats, an alien dodging meteors, or even a pizza slice flying through space!

This kind of reskinning is common in game development and is a fun way to stretch your creativity.

Is your game still happening in space? Or is it now on land, in water, or underground?

Who is the player, and what are they escaping from?


2.  Update your GameObjects using simple 2D shapes:

Just like you did with your ship, use child GameObjects and scale/rotate 2D primitives like triangles, rectangles, capsules, or hexagons to create your new character or obstacles.

Group them under a parent GameObject to retain their behaviour.

Note: You might need to remove, replace, or adjust the colliders based on the new shapes.

Tip: You don’t have to change any code for this step — but it might inspire future changes. A fresh theme could lead to new gameplay ideas, visuals, or sound effects.

Your game is currently built using Unity’s default shapes — and that’s a great way to prototype. But now that you have a full game loop, it’s a good time to replace those shapes with custom sprites or artwork. Whether you create your own or use free or paid assets, swapping visuals is an easy way to make your game feel more polished and original.

You can create your own sprites in a tool like Photoshop, Aseprite, or even MS Paint.

You can also browse free asset sites like the following:

In the Hierarchy window, select the Player, Obstacle, or Borders GameObject you want to reskin.

Tip: If you want to add a custom background, add a new square sprite and set its Order in Layer property to a negative number. This will make sure it appears behind the other sprites.

Assign your custom sprite in the Inspector window.

Disable the old Sprite Renderer component (used for the default shape).



You might need to tweak the Transform component on your new sprite to match your existing hitboxes or layout.

Use Unity’s 2D tools to align the visual element with the functional one.



4.  (Optional) Try animated sprite sheets:

If you want more visual flair, try replacing your thruster or obstacles with animated 2D sprite sheets.

Unity’s 2D Animation or Animator tools can help you play looping animations during gameplay.

Sprite Flight with the sprite changed. The Obstacles are now detailed renderings of asteroids, while the Player is a rendering of a spaceship. The background is a more layered rendering of space. At the top of the image, the Score label shows the current score of 19.

One of the easiest ways to give your game a more polished and professional look is to choose a cohesive color palette. Coordinating the colors of your player, obstacles, background, and UI elements can help everything feel like it belongs in the same world — even if you’re still using simple shapes.

Search online for “color palette generator” and explore some of the results.

Choose a palette that fits the mood of your game.



Copy the Hex code (for example. #FF6B6B) from the palette site.

In Unity, select a GameObject and select the Color swatch from its Sprite Renderer component.

Paste the Hex code into the Hexadecimal box.

Repeat this process for your Player, Obstacles, Borders, GameUI GameObjects, and the Main Camera GameObject’s Background color.



Make sure your score is readable against the background.

Use brighter or bolder colors for gameplay-critical elements.

Three views of Sprite Flight with the color scheme changed. On the left the borders are red, the obstacles and high score label are orange, and the player is cyan. In the middle, the borders are orange, the obstacles are green, the high score label is red, and the player is blue. On the right, the borders and obstacles are yellow, the high score label is red, and  the player is cyan.

Want to make your game feel more intense the longer a player survives? You can add difficulty progression by tweaking how obstacles behave. One surprisingly effective trick is to adjust the bounciness of their physics material — which gradually increases their speed with each bounce.

In the Project window, locate the 2D Physics Material used by your obstacles (The one you named PhysMat_Bouncy in the Make a flying obstacle prefab tutorial).


In the Inspector window, set Bounciness property to something slightly higher than 1.0, like 1.05 or 1.1.

This will cause the obstacles to gain speed each time they bounce off a surface.

Note: Too much bounciness can make GameObjects get out of control quickly — test different values to find a fun balance.

If the Obstacle GameObjects become too fast, the game can effectively become impossible. You can modify your obstacle script to limit their velocity using Rigidbody2D.linearVelocity.magnitude.

Try searching online or pasting your script into a tool like Unity Muse or ChatGPT and ask how to clamp velocity in Unity.

Tip: This technique works best when combined with other features like player upgrades to give the player a chance of surviving in more difficult circumstances.

If you added the increasing difficulty feature above, you might have noticed that the obstacles keep bouncing around the screen even after the player is destroyed. This can feel distracting or messy. One simple fix is to make the screen borders disappear on game over so obstacles fly off-screen instead of endlessly rebounding.

1.  Create a reference in your script to the Borders parent GameObject:


In PlayerController.cs, add the following new public GameObject variable:

Drag the Borders GameObject into the Player GameObject’s Border Parent box in the Inspector window.



2.  Disable the borders when the Player GameObject is destroyed:


In OnCollisionEnter2D(), before or after the explosion is triggered, add the following line of code:

Sound instantly makes your game feel more complete and satisfying. You can add background music to set the mood, and a sound effect to play when the player explodes. These little touches go a long way in making your game feel polished.

Right-click in the Hierarchy window and select Audio > Audio Source.

Download this demo music track, drag it into your Assets folder, and assign it to the Audio Resource box in the Audio Source component.

Enable Loop and reduce Volume to around 0.3 to avoid overpowering the sound effects.

Select the ExplosionEffect prefab in the Project window.

Add an Audio Source component directly to the prefab.

Download this demo explosion sound effect, drag it into your Assets folder, and assign it to the Audio Resource box in the Audio Source component.

Note: Since the prefab is instantiated when the Player GameObject is destroyed, the sound will play automatically when it appears.

Try one of the following resources for free sounds and music:

Want to make your game world feel more alive without changing how it plays? Adding a background particle system — like drifting stars, dust, or sparkles — can bring motion and atmosphere to your scene. It’s subtle, but it makes a big difference in how polished your game feels.

In the Hierarchy window, right-click and select Effects > Particle System.

Rename it “StarryBackground” (or something similar).



In the Inspector window, open the Shape section.

Set the Shape property to Box and set the Scale property so it matches your screen bounds.



Set the Start Size property to something small like 0.05.

Note: The Main section at the top of the Particle System component with the header that matches the name of the GameObject.

(Optional) In the Color over Lifetime section:

Add a fade-in and fade-out gradient using the Alpha curve.

4.  Make the particles go in random directions:

Enable the Velocity over Lifetime section.

Set the Linear property Random Between Two Constants. 

Set the minimum and maximum X and Y values to -1.0 and 1.0 to have the particles moving randomly in all 2D directions. 

Adding a small burst of animation and sound when the player moves can make the controls feel more responsive and fun. You can create a booster flame that appears when the player applies thrust  and that disappears when they release the mouse button, along with a matching sound effect. The best way to experience this impact of this feature is by playing the demo on Unity Play. 

If you haven’t already added a booster graphic, in the Hierarchy window, select your Player GameObject, add a child GameObject, and name it “BoosterFlame”.

Use a triangle or capsule shape (or a small flame sprite) and scale/rotate it to appear behind the Player GameObject.

Disable the BoosterFlame GameObject in the Inspector (disable the checkbox at the top).

In your PlayerController.cs script, add the following public reference:

Assign the reference in the Inspector window by dragging in the BoosterFlame child GameObject.

In Update(), check for input by adding the following lines of code:

if (Mouse.current.leftButton.wasPressedThisFrame) {
{
boosterFlame.SetActive(true);
}
else if (Mouse.current.leftButton.wasReleasedThisFrame)
{
boosterFlame.SetActive(false);
}

Add an Audio Source to the BoosterFlame GameObject.

Download this demo thruster sound effect, drag it into your Assets folder, and assign it to the Audio Resource box in the Audio Source component.

Enable Looping so the sound plays as long as the thruster is active.

You can also find another looping booster sound from the Unity Asset store or other online sound resources. 

You can use the Animator system to scale or flicker the flame over time.

You could also use a script to randomly change the flame’s size slightly every few frames for a random scaling or flickering effect.

The Scene view showing the Player GameObject with a booster flame added to it. The player GameObject and the BoosterFlame GameObject both have speaker icons on them, showing that they have audio sources attached to them. 

If you’d like to publish your game to mobile or WebGL with touch controls, this bonus feature shows you how to swap out the simpler mouse input for a more versatile Input Action. This Input Action allows you to track screen taps for thrust and finger position for aim, just like you did with a mouse.

In your PlayerController script, add the following public variables:

public InputAction moveForward;
public InputAction lookPosition;

Add the following using directive at the top of your script (if not already there):

2.  Add bindings in the Inspector window:

In the Inspector window, under your Player GameObject, find the two new action fields.

For moveForward, set the action type to Button, and add a binding with the path: Pointer > Press.

For lookPosition, set the action type to Value, and use the binding path: Pointer > Position.

Note: The Pointer input works for both mouse or touch on mobile. 

Inside Start(), enable both actions by adding the following code:

Optional bonus features

1. Overview

2. Change your entire game concept

3. Swap out your sprites

4. Create a cohesive color scheme

5. Increase difficulty over time

6. Destroy the borders on game over

7. Add sound effects and background music

8. Add ambient background particles

9. Animated booster graphic with audio

10. Make your game compatible with mobile

11. Next steps

Complete this tutorial