coin

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Coin : MonoBehaviour 
{
    //Create a reference to the CoinPoofPrefab
    public GameObject coinpoof;
    private static int coinsCollected = 0;

    public int CoinsCollected
    {
        get
        {
            return coinsCollected;
        }
        set
        {
            coinsCollected = value;
        }
    }

    public void OnCoinClicked()
    {
        Vector3 coinLocation = gameObject.transform.position;

        // Instantiate the CoinPoof Prefab where this coin is located
        // Make sure the poof animates vertically
        Instantiate(coinpoof, new Vector3(coinLocation.x, coinLocation.y, coinLocation.z), Quaternion.Euler(-100f, 0, 0));
        // Update the amount of Coins collected
        CoinsCollected++;
        // Destroy this coin. Check the Unity documentation on how to use Destroy
        Destroy(gameObject);
    }
}

door

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Door : MonoBehaviour 
{
    public AudioClip[] soundFiles;
    public AudioSource soundSource;
    // Create a boolean value called "locked" that can be checked in OnDoorClicked() 
    bool locked = true;
    // Create a boolean value called "opening" that can be checked in Update() 
    bool opening = false;
    private float fullHeight = 5.0f;
    void Update() {
        // If the door is opening and it is not fully raised
        if (opening && transform.position.y < fullHeight)
        {
            // Animate the door raising up
            transform.Translate(0, 2.5f * Time.deltaTime, 0);
        }

    }

    public void OnDoorClicked() {
        int doorLocked = 0;
        int doorOpen = 1;
        // If the door is clicked and unlocked
        if (!locked)
        // Set the "opening" boolean to true
        // (optionally) Else
        // Play a sound to indicate the door is locked
        {
            soundSource.clip = soundFiles[doorOpen];
            soundSource.Play();
            opening = true;
        }
        else
        {
            soundSource.clip = soundFiles[doorLocked];
            soundSource.Play();
        }
    }

    public void Unlock()
    {
        // You'll need to set "locked" to false here
        locked = false;
    }
}

    

key

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Key : MonoBehaviour 
{
    //Create a reference to the KeyPoofPrefab and Door
    public GameObject Door;
    public GameObject Keypoof;


    void Update()
	{
		//Not required, but for fun why not try adding a Key Floating Animation here :)
	}

	public void OnKeyClicked()
	{
        Vector3 keyLocation = gameObject.transform.position;
                // Instatiate the KeyPoof Prefab where this key is located
        // Make sure the poof animates vertically
        Instantiate(Keypoof, new Vector3(keyLocation.x, keyLocation.y, keyLocation.z), transform.rotation);
        // Call the Unlock() method on the Door
        Door.GetComponent<Door>().Unlock();
        // Destroy the key. Check the Unity documentation on how to use Destroy
        Destroy(gameObject);
    }

}