Alex教程每一P的教程原代码加上我自己的理解初步理解写的注释，可供学习Alex教程的人参考
此代码仅为较上一P有所改变的代码

【Unity教程】从0编程制作类银河恶魔城游戏_哔哩哔哩_bilibili

Crystal_Skill_Controller

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

public class Crystal_Skill_Controller : MonoBehaviour
{
    private Animator anim => GetComponent<Animator>();
    private CircleCollider2D cd => GetComponent<CircleCollider2D>();

    private float crystalExitTimer;

    private bool canExplode;
    private bool canMove;
    private float moveSpeed;

    private bool canGrow;
    private float growSpeed = 5;

   public void SetupCrystal(float _crystalDuration,bool _canExplode,bool _canMove,float _moveSpeed)
    {
        crystalExitTimer = _crystalDuration;
        canExplode = _canExplode;
        canMove = _canMove;
        moveSpeed = _moveSpeed;
    }
    private void Update()
    {
        crystalExitTimer -= Time.deltaTime;
        if (crystalExitTimer < 0)
        {
            FinishCrystal();
        }

        if (canGrow)
            transform.localScale = Vector2.Lerp(transform.localScale, new Vector2(3, 3), growSpeed * Time.deltaTime);

    }
    private void AnimationExplodeEvent()
    {
        Collider2D[] colliders = Physics2D.OverlapCircleAll(transform.position, cd.radius);
        foreach(var hit in colliders)
        {
            if (hit.GetComponent<Enemy>() != null)
                hit.GetComponent<Enemy>().Damage();
        }
          
    }

    public void FinishCrystal()
    {
        if (canExplode)
        {
            canGrow = true;
            anim.SetBool("Explode",true);
        }
        else
        {
            SelfDestory();
        }
    }

    public void SelfDestory() => Destroy(gameObject);
}

Crystal_Skill

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

public class Crystal_Skill : Skill
{
    [SerializeField] private GameObject crystalPrefab;
    [SerializeField] private float crystalDuration;
    private GameObject currentCrystal;

    [Header("Explosive crystal")]
    [SerializeField] private bool canExplode;

    [Header("Moving crystal")]
    [SerializeField] private bool canMoveToEnemy;
    [SerializeField] private float moveSpeed;

    public override bool CanUseSkill()
    {
        return base.CanUseSkill();
    }

    public override void UseSkill()
    {
        base.UseSkill();

        if (currentCrystal == null)
        {
            currentCrystal = Instantiate(crystalPrefab, player.transform.position, Quaternion.identity);
            Crystal_Skill_Controller currentCrystalScripts = currentCrystal.GetComponent<Crystal_Skill_Controller>();
            currentCrystalScripts.SetupCrystal(crystalDuration,canExplode,canMoveToEnemy,moveSpeed);
        }    
        else
        {
            Vector2 playerPos = player.transform.position;

            player.transform.position = currentCrystal.transform.position;

            currentCrystal.transform.position = playerPos;
            currentCrystal.GetComponent<Crystal_Skill_Controller>()?.FinishCrystal();
        }
    }

    protected override void Start()
    {
        base.Start();
    }

    protected override void Update()
    {
        base.Update();
    }
}