ofb/Assets/Scripts/ProjectileEnemy.cs

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

public class ProjectileEnemy : MonoBehaviour {

    [SerializeField] GameObject projectile;
    [SerializeField] GameObject firePoint;
    [SerializeField] [Range(0.1f, 3f)] float fireSpeed;
    [SerializeField] float projectileSpeed;

    // Start is called before the first frame update
    void Start() {
        StartCoroutine(Fire());
    }

    IEnumerator Fire() {
        yield return new WaitForSeconds(1/fireSpeed);
        GameObject newProjectile = Instantiate(projectile, firePoint.transform.position, firePoint.transform.rotation);
        newProjectile.GetComponent<Rigidbody2D>().AddRelativeForce(new Vector2(projectileSpeed, 0));
        newProjectile.transform.Rotate(new Vector3(0,0,-90));
        StartCoroutine(Fire());
    }
}