my bullet keeps firing up

I have implemented a bullet in the following manner, but it seems to just go up, what did i do wrong?

public class Player1Controls : MonoBehaviour {

 // Update is called once per frame 
 public float speed;
 Rigidbody2D player;
 public float health;
 private int state;
 public Rigidbody2D Bullet;
 public GameObject Gun;
 void Start ()
 {
     player = GetComponent<Rigidbody2D>();
 }
 void Update ()
 {
     if (Input.GetKeyDown(KeyCode.Space))
     {
         Rigidbody2D bullet1 = (Rigidbody2D)Instantiate (Bullet, Gun.transform.position,Quaternion.identity);
         bullet1.transform.position = Gun.transform.position;
         //bullet1.GetComponent<Rigidbody>().AddForce(transform.forward * speed);
         //Vector2 direction = player.velocity.normalized;
         //float ang = Vector2.Angle(player.transform.position, direction);
        // Vector3 cross = Vector3.Cross(player.transform.position, direction);

         //if (cross.z > 0)
             //ang = 360 - ang;

         //player.MoveRotation(ang);
     }
     if(Input.GetKey(KeyCode.W))
     {
         //transform.Translate(Vector2.up * speed);
         player.velocity =(Vector2.up*speed);
         state = 1;
     }

public class MoveBullet : MonoBehaviour {

 public float speed;
 // Update is called once per frame
 void Update () {
     Vector3 pos = transform.position;
     Vector3 vel = new Vector3(0, speed * Time.deltaTime, 0);
     pos = pos + transform.rotation * vel;
     transform.position = pos;
 }