我怎样才能使预制件从生成点完全反转（180度）？ Unity 2D

Question

So i made a little side scroller that uses a prefab to spawn bullets. My problem is that it only shoots to one side... the Right.
I need it to fire to the left as well. I've already made a variable to see if the player is looking to the right or left.

I've tried to put the Speed to -20 and i've tried to rotate it 180 degrees on it's Z axis. I tested if the bullet script even picked up the change from the player movement script and it does.

Player Movement script

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

public class PlayerMovement : MonoBehaviour
{
    public GameObject bullet;

    private Rigidbody2D myRigidbody;
    private float speed = 15;
    private bool facingRight;
    private bool ground = false;
    private float jump = 23;
    // Start is called before the first frame update
    void Start()
    {
        facingRight = true;
        myRigidbody = GetComponent<Rigidbody2D>();
    }

    // Update is called once per frame
    void FixedUpdate()
    {
        float horizontal = Input.GetAxis("Horizontal");

        Movement(horizontal);
        Flip(horizontal);
        if (Input.GetKey("w"))
        {
            if (ground)
            {
                GetComponent<Rigidbody2D>().velocity = new Vector2(GetComponent<Rigidbody2D>().velocity.x, jump);
            }
        }
        if(facingRight == false)
        {
            bullet.GetComponent<bullet>().left = true;
        }
        if (facingRight == true)
        {
            bullet.GetComponent<bullet>().left = false;
        }
    }

    void OnTriggerEnter2D()
    {
        ground = true;
    }

    void OnTriggerExit2D()
    {
        ground = false;
    }

    private void Movement(float horizontal)
    {

        myRigidbody.velocity = new Vector2(horizontal * speed,myRigidbody.velocity.y);
    }

    private void Flip(float horizontal)
    {
        if (horizontal > 0 && !facingRight || horizontal < 0 && facingRight)
        {
            facingRight = !facingRight;

            Vector3 theScale = transform.localScale;

            theScale.x *= -1;

            transform.localScale = theScale;
        }
    }


}

Weapon script

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

public class weapon : MonoBehaviour
{
    // Start is called before the first frame update
    public bool right;
    public Transform firepointR;

    public GameObject bulletPrefab;

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKeyDown("space"))
        {
            Debug.Log("Oh well");
            Shoot();
        }

    }

    void Shoot()
    {
            Instantiate(bulletPrefab, firepointR.position, firepointR.rotation);
    }
}

bullet script

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

public class bullet : MonoBehaviour
{
    public bool left;
    public float speed = 20;

    public Rigidbody2D rb;
    // Start is called before the first frame update
    void Start()
    {
        rb.velocity = transform.right * speed;
    }

    // Update is called once per frame
    void FixedUpdate()
    {
        Debug.Log(speed);

        if (left == false)
        {
            transform.Rotate(0, 0, 180);
        }
    }
}

As i previously said i need my bullet (prefab) to go the opposite direction but whatever i do right now it will always go right.

Answer 1

Expanding on my comment:

Did you try reversing the velocity?

rb.velocity = -(transform.right * speed);

Note: There are instances when using a negative float wont return the opposite of the positive result. However, in this example, it will work just fine.

I imagine this will work also ( and is probably the correct way of doing it ):

rb.velocity = transform.left * speed;