Kill Player Method Doesn't Work ?

Can you help me with this? Punji sticks "I added Box Collider." "I added Instakill.cs." But he does not kill the player!

LevelManager.cs

using UnityEngine; using System; using System.Linq;

public class LevelManager : MonoBehaviour { public static LevelManager Instance {get; private set;}

 public Player Player {get; private set;}

 public CameraController Camera {get; private set;}

 private List<Checkpoint> _checkpoints;
 private int _currentCheckpointIndex;

 public Checkpoint DebugSpawn;

 public void Awake()
 {
     Instance = this;
 }

 public void Start ()
 {
     // sorts check points by X axis 
     _checkpoints = FindObjectsOfType<Checkpoint>().OrderBy(t => t.transform.position.x).ToList();

     // if check point  are more then 0 set checkpoint count to 0 is no checkpoints set checkpoints count to -1
     _currentCheckpointIndex = _checkpoints.Count > 0 ? 0 : -1;

     Player = FindObjectOfType<Player>();
     Camera = FindObjectOfType<CameraController>();

     //debug if will not appear outside of unity editor         
     #if UNITY_EDITOR      
     if (DebugSpawn != null)
         DebugSpawn.SpawnPlayer(Player);
     else if (_currentCheckpointIndex != -1)
         _checkpoints[_currentCheckpointIndex].SpawnPlayer(Player);
     #else
     //standard "production" if
     if (_currentCheckpointIndex != -1)
     _checkpoints[_currentCheckpointIndex].SpawnPlayer(Player);
     #endif
 }
 public void Update()
 {
     //checks if at last checkpoint
     var isAtLastCheckpoint = _currentCheckpointIndex + 1 >= _checkpoints.Count;
     if (isAtLastCheckpoint)
         return;

     //checks distance from next check point
     var distanceToNextCheckpoint = _checkpoints[_currentCheckpointIndex +1].transform.position.x - Player.transform.position.x;
     if (distanceToNextCheckpoint >= 0)
         return;

     //registers player leaving last checkpoint 
     _checkpoints[_currentCheckpointIndex].PlayerLeftCheckpoint();
     //updates checkpoint index
     _currentCheckpointIndex++;
     //Player hit new checkpoint
     _checkpoints[_currentCheckpointIndex].PlayerHitCheckpoint();

     //TODO: adjustment for player hitting a check point
 }

 public void KillPlayer()
 {
     StartCoroutine(KillPlayerCo());
 }

 private IEnumerator KillPlayerCo()
 {
     Player.Kill();
     Camera.IsFollowing = false;
     //gives control to unity for float #
     yield return new WaitForSeconds(2f);

     Camera.IsFollowing = true;

     if (_currentCheckpointIndex != -1)
         _checkpoints[_currentCheckpointIndex].SpawnPlayer(Player);

     //TODO: death adjustments
 }

}

CheckPoint.cs

using System.Collections; using UnityEngine;

public class Checkpoint : MonoBehaviour {

 public void PlayerHitCheckpoint()
 {
 }

 private IEnumerator PlayerHitCheckpointCo(int bonus)
 {
     yield break;
 }

 public void PlayerLeftCheckpoint()
 {
 }

 public void SpawnPlayer(Player player)
 {
     player.RespawnAt(transform);
 }

 public void AssignObjectToCheckpoint()
 {
 }

}

Player.cs

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

public class Player : MonoBehaviour { private bool _isFacingRight; private CharacterController2D _controller; private float _normalizedHorizontalSpeed;

 public float MaxSpeed = 12;
 public float SpeedAccelerationOnGround = 10f;
 public float SpeedAccelerationInAir = 5f;

 public bool IsDead { get; private set; }

 public void Awake()

 {
     _controller = GetComponent<CharacterController2D> ();
     _isFacingRight = transform.localScale.x > 0;

 }

 public void Update ()
 {
     if (!IsDead)
     HandleInput ();

     var movementFactor = _controller.State.IsGrounded ? SpeedAccelerationOnGround : SpeedAccelerationInAir;
     _controller.SetHorizontalForce (Mathf.Lerp (_controller.Velocity.x, _normalizedHorizontalSpeed * MaxSpeed, Time.deltaTime * movementFactor));

 }

 public void Kill()
 {
     _controller.HandleCollisions = false;
     this.gameObject.GetComponent<Collider2D>().enabled = false;
     IsDead = true;
 }

 public void RespawnAt(Transform spawnPoint)
 {
     if (!_isFacingRight)
         Flip ();
     IsDead = false;
     this.gameObject.GetComponent<Collider2D>().enabled = true;
     _controller.HandleCollisions = true;

     transform.position = spawnPoint.position;
 }

 private void HandleInput()
 {
     if (Input.GetKey (KeyCode.D)) 
     {
         _normalizedHorizontalSpeed = 1;
         if (!_isFacingRight)
             Flip ();
     } 
     else if (Input.GetKey (KeyCode.A)) 
     {
         _normalizedHorizontalSpeed = -1;
         if (_isFacingRight)
             Flip ();
     } 
     else 
     {
         _normalizedHorizontalSpeed = 0;
     }
     if (_controller.CanJump && Input.GetKeyDown (KeyCode.Space)) 
     {
         _controller.Jump ();
     }
 }

 private void Flip()
 {
     transform.localScale = new Vector3(-transform.localScale.x,transform.localScale.y,transform.localScale.z);
     _isFacingRight = transform.localScale.x > 0;
 }

}

InstaKill.cs

using UnityEngine;

public class InstaKill : MonoBehaviour { public void OnTriggerEnter2D(Collider2D other) { var player = other.GetComponent(); if (player == null) return;

     LevelManager.Instance.KillPlayer();
 }

}