Untitled

public class SceneLoader : MonoBehaviour
{
//Scene1
    void Start()
    {
        Debug.Log("Scene1 started");

        if (!PlayerPrefs.HasKey("Score"))
        {
             PlayerPrefs.SetInt("Score", 1);
        }

        Debug.Log(PlayerPrefs.GetInt("Score"));
      
    }

    void Update()
    {
        if(Input.anyKey)
        {
            SceneManager.LoadScene(1);
        }
    }
}
---------------------------------------------------
Scene2
public class SceneLoader2 : MonoBehaviour
{
    void Start()
    {
        Debug.Log("Scene2 start");
        int score = PlayerPrefs.GetInt("Score");
        score++;

        PlayerPrefs.SetInt("Score", score);
        Debug.Log(score);
    }

    void Update()
    {
        if (Input.anyKey)
        {
            SceneManager.LoadScene(0);
        }
    }
}