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

Enemy.cs

using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;

public class Enemy : Entity
{
    [SerializeField] protected LayerMask whatIsPlayer;
    [Header("Stun Info")]
    public float stunnedDuration;//stunned持续时间
    public Vector2 stunnedDirection;//stunned改变后的速度
    protected bool canBeStunned;//判断是否可以被反击
    [SerializeField] protected GameObject counterImage;//一个代表着是否可以被反击的信号

    [Header("Move Info")]
    public float moveSpeed;
    public float idleTime;
    public float battleTime;//多久能从battle状态中退出来
    [Header("Attack Info")]
    public float attackDistance;
    public float attackCooldown;//攻击冷却
    [HideInInspector] public float lastTimeAttacked;//最后一次攻击的时间

    #region 类
    public EnemyStateMachine stateMachine;

    #endregion

    protected override void Awake()
    {
        base.Awake();
        stateMachine = new EnemyStateMachine();

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

    }


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

        stateMachine.currentState.Update();

        //Debug.Log(IsPlayerDetected().collider.gameObject.name + "I see");//这串代码会报错，可能使版本的物体，因为在没有找到Player的时候物体是空的，NULL，你想让他在控制台上显示就报错了
    }

    public virtual void OpenCounterAttackWindow()//打开可以反击的信号的函数
    {
        canBeStunned = true;
        counterImage.SetActive(true);
    }
    public virtual void CloseCounterAttackWindow()//关闭可以反击的信号的函数
    {
        canBeStunned = false;
        counterImage.SetActive(false);
    }

    //protected virtual bool CanBeStunned()//没搞懂
    //{
    //    if(canBeStunned)
    //    {
    //        CloseCounterAttackWindow();
    //        return true;
    //    }
    //    return false;

    //}
    public virtual void AnimationFinishTrigger() => stateMachine.currentState.AnimationFinishTrigger();//动画完成时调用的函数，与Player相同
    public virtual RaycastHit2D IsPlayerDetected() => Physics2D.Raycast(wallCheck.position, Vector2.right * facingDir, 7, whatIsPlayer);//用于从射线投射获取信息的结构。
    //该函数的返回值可以变，可以只返回bool，也可以是碰到的结构

    protected override void OnDrawGizmos()
    {
        base.OnDrawGizmos();

        Gizmos.color = Color.yellow;//把线改成黄色
        Gizmos.DrawLine(transform.position, new Vector3(transform.position.x + attackDistance * facingDir, transform.position.y));//用来判别是否进入attackState的线
    }


}

Enemy_Skeleton.cs

using System.Collections;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEditorInternal;
using UnityEngine;

public class Enemy_Skeleton : Enemy
{
    #region 类State
    public SkeletonIdleState idleState { get; private set; }
    public SkeletonMoveState moveState { get; private set; }
    public SkeletonBattleState battleState { get; private set; }
    public SkeletonAttackState attackState { get; private set; }
    public SkeletonStunnedState stunnedState { get; private set; }
    #endregion
    protected override void Awake()
    {
        base.Awake();

        idleState = new SkeletonIdleState(this, stateMachine, "Idle", this);
        moveState = new SkeletonMoveState(this,stateMachine, "Move", this);
        battleState = new SkeletonBattleState(this, stateMachine, "Move", this);
        attackState = new SkeletonAttackState(this, stateMachine, "Attack", this);
        stunnedState = new SkeletonStunnedState(this, stateMachine, "Stunned", this);

    }

    protected override void Start()
    {
        base.Start();
        stateMachine.Initialize(idleState);
    }

    protected override void Update()
    {
        base.Update();
        
        if(Input.GetKeyDown(KeyCode.U))
        {
            stateMachine.ChangeState(stunnedState);//暂时用U来控制进入stunned
        }
    }

    //protected override bool CanBeStunned()
    //{
    //    if(base.CanBeStunned())
    //    {
    //        stateMachine.ChangeState(stunnedState);
    //        return true;
    //    }
    //    return false;
    //}
}

Enemy_SkeletonAnimationTrigger.cs

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

public class Enemy_SkeletonAnimationTriggers : MonoBehaviour
{
    private Enemy_Skeleton enemy => GetComponentInParent<Enemy_Skeleton>();//拿到enemy实体
    private void AnimationTrigger()
    {
        enemy.AnimationFinishTrigger();//调用实体上的函数，使triggerCalled为true；
    }

    private void AttackTrigger()
    {
        Collider2D[] colliders = Physics2D.OverlapCircleAll(enemy.attackCheck.position, enemy.attackCheckRadius);//创建一个碰撞器组，保存所有圈所碰到的碰撞器
        //https://docs.unity3d.com/2022.3/Documentation/ScriptReference/Physics2D.OverlapCircleAll.html
        foreach (var hit in colliders)//https://blog.csdn.net/m0_52358030/article/details/121722077
        {
            if (hit.GetComponent<Player>() != null)
            {
                hit.GetComponent<Player>().Damage();
            }
        }
    }
    private void OpenCounterWindow() => enemy.OpenCounterAttackWindow();
    private void CloseCounter() => enemy.CloseCounterAttackWindow();
}