Unity freezes when I try to click play

I recent edited a script from this: public class FPSController : MonoBehaviour {

     public float Speed = 5.0f; 
     public float StaticSpeed = 5.0f; 
     //StaticSpeed MUST be equal to Speed. 
     public float SprintSpeed = 8.0f; 
     public float Sensitivity = 2.0f; 
      
 
     CharacterController player; 
 
     public GameObject Eyes; 
     public GameObject Player; 
 
     private bool isSprinting = false; 
     private bool isMouseLocked = true; 
 
     float moveFB; 
     float moveLR; 
 
     float rotX; 
     float rotY; 
 
     void Start () {
         player = GetComponent<CharacterController> (); 
     }
 
     void Update () {
 
         if (Input.GetButtonDown ("Unlock")) {
             isMouseLocked = !isMouseLocked; 
         }
 
         if (isMouseLocked == true) {
             Cursor.lockState = CursorLockMode.Locked; 
             Cursor.visible = false; 
         }
 
         if (isMouseLocked == false) {
             Cursor.lockState = CursorLockMode.None; 
             Cursor.visible = true; 
         }
             
 
         moveFB = Input.GetAxis ("Vertical") * Speed; 
         moveLR = Input.GetAxis ("Horizontal") * Speed; 
 
         if (Input.GetButtonDown ("Sprint")) {
             isSprinting = true;
         }
 
         if (Input.GetButtonUp ("Sprint")) {
             isSprinting = false; 
         }
 
         if (isSprinting == true) {
             Speed = SprintSpeed; 
         }
 
         if (isSprinting == false) {
             Speed = StaticSpeed; 
         }
 
         rotY = Input.GetAxis ("Mouse Y") * Sensitivity; 
         rotX = Input.GetAxis ("Mouse X") * Sensitivity; 
 
         Vector3 Movement = new Vector3 (moveLR, 0, moveFB); 
         Player.transform.Rotate (0, rotX, 0); 
         Eyes.transform.Rotate (-rotY, 0, 0); 
 
         Movement = transform.rotation * Movement; 
         player.Move (Movement * Time.deltaTime); 
 
 
     }
 }
 

To this:

 public class FPSController : MonoBehaviour {
 
     public float Speed = 5.0f; 
     public float StaticSpeed = 5.0f; 
     //StaticSpeed MUST be equal to Speed. 
     public float SprintSpeed = 8.0f; 
     public float Sensitivity = 2.0f; 
     public float jumpVelocity = 5.0f; 
     public float Gravity = 2.0f; 
 
     CharacterController player; 
 
     public GameObject Eyes; 
     public GameObject Player; 
 
     private bool isSprinting = false; 
     private bool isMouseLocked = true; 
 
     float moveFB; 
     float moveLR; 
 
     float rotX; 
     float rotY; 
 
     void Start () {
         player = GetComponent<CharacterController> (); 
     }
 
     void Update () {
 
         if (Input.GetButtonDown ("Unlock")) {
             isMouseLocked = !isMouseLocked; 
         }
 
 
         while (player.isGrounded == true) {
             if (Input.GetButtonDown ("Jump")) {
                 Jump ();  
             }
         }
 
         while (player.isGrounded == false) {
             transform.Translate (Vector3.down * Gravity * Time.deltaTime); 
         }
 
         if (isMouseLocked == true) {
             Cursor.lockState = CursorLockMode.Locked; 
             Cursor.visible = false; 
         }
 
         if (isMouseLocked == false) {
             Cursor.lockState = CursorLockMode.None; 
             Cursor.visible = true; 
         }
             
 
         moveFB = Input.GetAxis ("Vertical") * Speed; 
         moveLR = Input.GetAxis ("Horizontal") * Speed; 
 
         if (Input.GetButtonDown ("Sprint")) {
             isSprinting = true;
         }
 
         if (Input.GetButtonUp ("Sprint")) {
             isSprinting = false; 
         }
 
         if (isSprinting == true) {
             Speed = SprintSpeed; 
         }
 
         if (isSprinting == false) {
             Speed = StaticSpeed; 
         }
 
         rotY = Input.GetAxis ("Mouse Y") * Sensitivity; 
         rotX = Input.GetAxis ("Mouse X") * Sensitivity; 
 
         Vector3 Movement = new Vector3 (moveLR, 0, moveFB); 
         Player.transform.Rotate (0, rotX, 0); 
         Eyes.transform.Rotate (-rotY, 0, 0); 
 
         Movement = transform.rotation * Movement; 
         player.Move (Movement * Time.deltaTime); 
 
 
     }
 
     void Jump () {
         transform.Translate (Vector3.up * jumpVelocity * Time.deltaTime);
     }
 }
 
 

And now whenever I try to play with this script, the Unity Editor goes dark like it's going to play, but never does. Why did this happen, and how do I fix it?