Rotation using Unity2D

Is this a 3D game or a 2D game? What code have you tried that did not work out? When the rotation of the object (0,0,0), what side of the object is the 'forward'...that is the side you want to point at the mouse?

2D Game, hence the subject name "Rotation using Unity2D"

Here's my LookAt script that also fires a bullet. I edited this code from an example.

 var dir : Vector3;
 private var tempVector : Vector3;                //We need this to figure out where to look
 private var tempVector2 : Vector3;                //We need this to figure out where to look
 private var lookDir : Vector3;                    //The look direction
 public var bullet : GameObject;                    //Bullet prefab
 
 
 public var fireTime : float;                    //Fire time
 private var tmpFireTime : float;                //Tmp fire time
 public var spawnBulletPosition : Transform;        //Bullet Spawn position
 
 function Start () 
 {
 
 }
 
 function Update ()
 {
     //If the game is not running on a android device
     if (Application.platform != RuntimePlatform.Android)
     {
         //Horizontal axis and Vertical axis is not 0
         if (Input.GetAxis("Horizontal") != 0 || Input.GetAxis("Vertical") != 0)
         {
             //Set dir x to Horizontal and dir z to Vertical
             dir = new Vector3(Input.GetAxis("Horizontal"),Input.GetAxis("Vertical"), -10);
         }
         else
         {
             //Set dir to 0
             dir = new Vector3(0,0,0);
         }
         //Find the center of the screen
         tempVector2 = new Vector3(Screen.width * 0.5f,0,Screen.height * 0.5f);
         //Get mouse position
         tempVector = Input.mousePosition;
         //Set tempVector z to tempVector.y
         ///tempVector.z = tempVector.y;
         //Set tempVector y to 0
         //tempVector.y = 0;
         //Set lookDir to  tempVector - tempVector2
         lookDir = tempVector - tempVector2;
         
         //If left mouse click
         if (Input.Get$$anonymous$$ouseButton(0))
         {
             //Check to see if we can fire yet.
             if (tmpFireTime >= fireTime)
             {
                 //Set tmpFireTime to 0
                 tmpFireTime = 0;
                 //Instantiate bullet                                                        
                 var go = Instantiate(bullet, spawnBulletPosition.position, Quaternion.LookRotation(lookDir)) as GameObject;
                 go.rigidbody2D.AddForce(go.transform.forward * -700);
             }
             //Couldn't fire yet
             else if (tmpFireTime < fireTime)
             {
                 //Add 1 to tmpFireTime
                 tmpFireTime += 1 * Time.deltaTime;
             }
         }
     }
     
     //Rotate Turret
     transform.rotation = Quaternion.LookRotation(lookDir);    
 }

This code cause the game object to rotate and tilt in incorrect directions ins$$anonymous$$d of how I want it to in the example image.

See how it tilts incorrectly?