using System.Collections;
using System.Collections.Generic;
using UnityEngine;
// ★追加
using TMPro;

public class ScoreManager : MonoBehaviour
{
    public TextMeshProUGUI scoreLabel;

    private int score;

    void Start()
    {
        // 0埋めのテクニック（0を何個並べるかは自由。ここでは15個）
        scoreLabel.text = "" + score.ToString("D15");
    }

    // メソッド経由でscoreの値を変更する。
    public void AddScore(int amount)
    {
        score += amount;
        scoreLabel.text = "" + score.ToString("D15");
    }
}

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

public abstract class EnemyBase : MonoBehaviour
{
    public int HP;

    // ★追加（スコア）
    public int ScoreValue;

    public virtual void TakeDamage(int missilePower)
    {
        HP -= missilePower;

        if (HP < 1)
        {
            Destroy(gameObject);

            // ★追加（スコア）
            GameObject.Find("ScoreManager").GetComponent<ScoreManager>().AddScore(ScoreValue);
        }
    }
}

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

public class MoveEnemyA : EnemyBase
{
    private float x;
    private float z;
    private float speed;

    void Start()
    {
        HP = 1;
        StartCoroutine(MoveE());

        // ★追加（スコア）
        ScoreValue = 100;
    }

    void Update()
    {
        transform.Translate(new Vector3(x, 0, z) * speed * Time.deltaTime, Space.World);
    }

    private IEnumerator MoveE()
    {
        x = 0;
        z = -1;
        speed = 5;

        yield return new WaitForSeconds(3f);

        x = 1;
        z = 0;
        speed = 10;
    }
}