Unity 2D Tutorial for Beginners: Keep Building Your “Catch Game” with C#

Step 1. Load Your Project

Ok, let's go. Start Unity and open the Catch Game project you created in Part 1. You can find your scene in the Assets window and double-click to load it. If you missed Part 1, you can 🎣go back and follow it here🎣.

Once your scene is open, your Unity Editor should now look like this:

Step 2. Add Side Walls

Our player can fall off the scene on the left or right. To stop this, we’ll add invisible walls. Create a new empty GameObject — either via GameObject → Create Empty or by right-clicking in the Hierarchy window and choosing Create Empty. Rename it to LeftWall.

With LeftWall selected, go to the Inspector and click Add Component → Physics 2D → Box Collider 2D. Then click Edit Collider and adjust it in the scene view using the green handles. Use the Move Tool to position the wall on the left side of the scene. Make sure the Z position is 0. You can assign a gizmo icon for better visibility if you want.

To make the second wall, just duplicate the LeftWall: right-click it in the Hierarchy and select Duplicate. Rename the copy to RightWall and move it to the right side. Now the player can’t fall out of bounds.

Step 3. Add a Score Display

Let’s add a simple interface to show the score on screen. Go to GameObject → UI → Text - TextMeshPro. Unity will automatically create a Canvas, the Text (TMP) object, and an EventSystem. If it's your first time using TextMeshPro, Unity may ask to import TMP Essentials — just click Import.

Double-click on Canvas in the Hierarchy to focus the UI view — you’ll see a white rectangle that represents the screen. Select Canvas and in the Inspector, change UI Scale Mode to Scale with Screen Size so the UI adjusts correctly.

Rename the text object to Score. In the Inspector, set its text to 00. Enable Auto Size and set the Alignment to center both horizontally and vertically. Then use the Rect Tool to move and resize the text box — place it near the top of the screen.

💡 Tip: TextMeshPro UI elements don’t move like sprites — you're moving their container. Use the Rect Tool (T) to move and resize the text box.

💡 Tip: The TextMeshPro Inspector has many settings. You only need to change a few — we’ll keep it simple and clean.

Step 4. Show the Score with Code

Let’s go back to the main game view. You can double-click the Main Camera in the Hierarchy to focus it, or switch to the Game tab to see the full game view.

Now we’ll make the score text update during gameplay. Open the ItemChecker script (double-click it in the Assets window). To work with the TextMeshPro UI system, add this line at the top:

using TMPro;

We'll create a reference to the Score object and access its text component, then update the display each time the score changes. Here’s the full version of the updated script:

using UnityEngine;
using TMPro;

public class ItemChecker : MonoBehaviour
{
    // Variable to store the current score
    public int score;

    // Drag your Score text object here in the Inspector (on the Canvas)
    public GameObject scoreTextObject;

    // Internal link to the TMP_Text component so we can change the text
    private TMP_Text tmpText;

    void Start()
    {
        // Find the TMP_Text component on the Score object
        tmpText = scoreTextObject.GetComponent<TMP_Text>();
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        // If we caught an object tagged "Good", increase the score by 10
        if (other.gameObject.tag == "Good")
        {
            score += 10;
            // Remove the item from the scene
            Destroy(other.gameObject);
        }

        // If we caught an object tagged "Bad", decrease the score by 10
        if (other.gameObject.tag == "Bad")
        {
            score -= 10;
            // Remove the item from the scene
            Destroy(other.gameObject);
        }

        // Update the text on the Canvas to show the new score
        tmpText.text = score.ToString();
    }
}

Don’t forget to drag your Score UI object into the Score Text Object field in the ItemChecker script component on your player.

In this script, we create a direct reference to the text component that displays the score. In step 3, we manually changed it by typing 00 into the field. Now we’re doing the same thing, but updating it through code.

The script waits for an event when a falling object touches the catcher. It then checks the tag to see what kind of object it is, updates the score variable accordingly, and finally changes the text component to show the current score.

Step 5. Add Sound Effects

Let’s bring our game to life with sound by adding sound effects for catching items. We’ll use a simple method: add an AudioSource to the player, then play sounds directly from our script.

First, select your player in the Hierarchy and click Add Component. Choose AudioSource. Leave all settings as default — we’ll use it for short sound effects only.

Then open your ItemChecker script and update it like this:

using UnityEngine;
using TMPro;

public class ItemChecker : MonoBehaviour
{
    // Variable to store the current score
    public int score;

    // Drag your Score text object here in the Inspector (on the Canvas)
    public GameObject scoreTextObject;

    // Internal reference to the TMP_Text component so we can update the text
    private TMP_Text tmpText;

    // Field for the "ok" sound clip
    public AudioClip okSound;

    // Field for the "boom" sound clip
    public AudioClip boomSound;

    // Reference to the AudioSource component
    private AudioSource audioSource;

    void Start()
    {
        // Find the TMP_Text component on the Score object
        tmpText = scoreTextObject.GetComponent<TMP_Text>();

        // Find the AudioSource component on this object
        audioSource = GetComponent<AudioSource>();
    }

    void OnTriggerEnter2D(Collider2D other)
    {
        // Play a sound depending on the tag
        if (other.tag == "Good")
        {
            audioSource.PlayOneShot(okSound);
        }
        else if (other.tag == "Bad")
        {
            audioSource.PlayOneShot(boomSound);
        }

        // If we caught an object tagged "Good", increase the score by 10
        if (other.gameObject.tag == "Good")
        {
            score += 10;
            // Remove the object from the scene
            Destroy(other.gameObject);
        }

        // If we caught an object tagged "Bad", decrease the score by 10
        if (other.gameObject.tag == "Bad")
        {
            score -= 10;
            // Remove the object from the scene
            Destroy(other.gameObject);
        }

        // Update the text on the Canvas to show the current score
        tmpText.text = score.ToString();
    }
}

You can download the sound effects used in this tutorial here:

• 🎧 Ok.wav — sound for catching a good item
• 💥 Boom.wav — sound for catching a bad item

Import the files into Unity.

Drag and drop the Ok and Boom audio files from the Assets folder into the matching fields in the ItemChecker component.

💡 Tip: You can adjust volume directly in the AudioSource component if sounds are too loud or quiet.

Step 10. Or… Just Keep It Simple

There’s no real Step 10 — not because there’s nothing left to do, but because this is a good place to pause. There are many ways to expand this game: you could add side triggers so the player only catches objects from above, or even change the tags of objects dynamically.

But the goal here wasn’t to make something big. It was to show something clear. If you're new to Unity — start easy. Build one thing that works. Later, you can always do more.

And who knows — maybe this little catch game will grow into something else. Change the falling objects into cars, replace the background with a road… and suddenly, it’s a driving game. 😉

That’s it for Part 2 — nice work! 🎉