top down shooting in unity 2D

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

public class Shooting : MonoBehaviour
{

    public Transform firePoint;
    public GameObject bulletPrefab;

    public float bulletForce = 20f;

    // Update is called once per frame
    void Update()
    {
        if(Input.GetButtonDown("Fire1"))
        {
            Shoot();
        }
    }  

    void Shoot()
    {
        GameObject bullet = Instantiate(bulletPrefab, firePoint.position, firePoint.rotation);
        Rigidbody2D rb = bullet.GetComponent<Rigidbody2D>();
        rb.AddForce(firePoint.up * bulletForce, ForceMode2D.Impulse);
    }

}

public float Speed = 5f; 

private void Update()
    {
        input = new Vector3(Input.GetAxisRaw("Horizontal"), Input.GetAxisRaw("Vertical"), 0);
        Vector3 velocity = input.normalized * Speed;
        transform.position += velocity * Time.deltaTime;
    }