Animations don't Update

Hey there! So I made a top-down character controller using RigidBody2D, and it works pretty well, but I've noticed that if I hold down say A and W, and then release the button I held down second, that second button's animation continues playing. Is there any way to fix this?

playerController.cs

    void Update()
     {
         //Moving Left
         if (Input.GetKeyDown(KeyCode.A))
         {
                 anim.Play("walk-left");
                 horizontal += -5;
                 direction = 4;
                 this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
         else if (Input.GetKeyUp(KeyCode.A))
         {
             horizontal += 5;
             this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
 
         //Moving Right
         if (Input.GetKeyDown(KeyCode.D))
         {
             anim.Play("walk-right");
             horizontal += 5;
             direction = 2;
             this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
         else if (Input.GetKeyUp(KeyCode.D))
         {
             horizontal += -5;
             this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
 
         //Moving Up
         if (Input.GetKeyDown(KeyCode.W))
         {
                 vertical += 5;
                 anim.Play("walk-up");
                 direction = 1;
                 this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
         else if (Input.GetKeyUp(KeyCode.W))
         {
             vertical += -5;
             this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
         
         //Moving Down
         if (Input.GetKeyDown(KeyCode.S))
         {
                 anim.Play("walk-down");
                 vertical += -5;
                 direction = 3;
                 this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
         else if (Input.GetKeyUp(KeyCode.S))
         {
 
             vertical += 5;
             this.GetComponent<Rigidbody2D>().velocity = new Vector2(horizontal, vertical);
         }
 
         if (this.GetComponent<Rigidbody2D>().velocity.magnitude <= 0)
         {
             if (direction == 1)
             {
                 anim.Play("idle-up");
             }
             if (direction == 2)
             {
                 anim.Play("idle-right");
             }
             if (direction == 3)
             {
                 anim.Play("idle-down");
             }
             if (direction == 4)
             {
                 anim.Play("idle-left");
             }
         }
     }