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

AudioManager.cs

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

public class AudioManager : MonoBehaviour
{
    public static AudioManager instance;

    [SerializeField] private float sfxMinimumDistance;
    [SerializeField] private AudioSource[] sfx;
    [SerializeField] private AudioSource[] bgm;

    public bool playBgm;
    private int bgmIndex;

    private void Awake()
    {
        if (instance != null)
        {
            Destroy(instance.gameObject);
        }
        else
            instance = this;

    }

    private void Update()
    {
        if (!playBgm)
            StopAllBGM();
        else
        {
            if (!bgm[bgmIndex].isPlaying)
                PlayBGM(bgmIndex);
        }
    }

    public void PlaySFX(int _sfxIndex,Transform _source)
    {
        if (sfx[_sfxIndex].isPlaying)//防止出现多个相同物体同时发出声音
        {
            return;
        }
        if (_source != null && Vector2.Distance(PlayerManager.instance.player.transform.position, _source.position) > sfxMinimumDistance)//防止东西很远的情况下发出声音
            return;

        if(_sfxIndex < sfx.Length)
        {
            sfx[_sfxIndex].pitch = Random.Range(.85f, 1.1f);
            sfx[_sfxIndex].Play();
        }
    }

    public void StopSFX(int _sfxIndex)
    {
        sfx[_sfxIndex].Stop();
    }
    public void PlayRandomBGM()
    {
        bgmIndex = Random.Range(0, bgm.Length);
        PlayBGM(bgmIndex);
    }
    public void PlayBGM(int _bgmIndex)
    {
        bgmIndex = _bgmIndex;
        StopAllBGM();
        if (_bgmIndex < sfx.Length)
        {
            bgm[_bgmIndex].Play();
        }
    }

    public void StopAllBGM()
    {
        for(int i = 0; i < bgm.Length; i++)
        {
            bgm[i].Stop();
        }
    }
}

 SkeletonIdleState.cs

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

public class SkeletonIdleState : SkeletonGroundState
{
    public SkeletonIdleState(Enemy _enemyBase, EnemyStateMachine _stateMachine, string _animBoolName, Enemy_Skeleton _enemy) : base(_enemyBase, _stateMachine, _animBoolName, _enemy)
    {
    }

    public override void Enter()
    {
        base.Enter();
        AudioManager.instance.PlaySFX(24, enemy.transform);
        stateTimer = enemy.idleTime;
    }

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

       
    }

    public override void Update()
    {
        base.Update();
        if(stateTimer < 0)
        {
            stateMachine.ChangeState(enemy.moveState);
        }
    }
}

playerAnimationTriggers.cs

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

public class playerAnimationTriggers : MonoBehaviour
{
    private Player player => GetComponentInParent<Player>();//获得夫组件上的实际存在的Player组件
    private void AnimationTrigger()
    {
        player.AnimationTrigger();
    }
    private void AttackTrigger()
    {
        AudioManager.instance.PlaySFX(2,null);

        Collider2D[] colliders = Physics2D.OverlapCircleAll(player.attackCheck.position, player.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<Enemy>()!=null)
            {
                EnemyStats _target = hit.GetComponent<EnemyStats>();

                if(_target != null)//修复无敌人时触发DoDamge出错的bug
                    player.stats.DoDamage(_target);//提供一个可以从player调用敌人受伤函数的入口，通过传入受伤敌人的组件

                if(Inventory.instance.GetEquipment(EquipmentType.Weapon) != null)//攻击带装备特效
                Inventory.instance.GetEquipment(EquipmentType.Weapon).Effect(_target.transform);

                // hit.GetComponent<Enemy>().DamageImpact();

            }
        }
    }

    private void ThrowSword()
    {
        SkillManager.instance.sword.CreateSword();
    }
}