Need suggestion or advice on my 2d platformer

Need suggestion or advice on my 2d platformer

Hi, this is my first time posting in here. I have been studying how to create a 2D platformer for nearly a week. I used the GBA Castlevania Aria of Sorrow as the reference to recreate the control on Soma Cruz. I have recreated a few of his major movement with animation controller. Currently I am having a problem deciding how to arrange or change the node in the Animator, because it have become messy.

There are two think I need help with.

1- What further improvement can I do to the Animator controller (Image below)?

2- I need some criticism on the PlayerController C# Script I have.

Thanks

 void Start ()
     {
         r2d = GetComponent<Rigidbody2D> ();
         cColl = GetComponent<CircleCollider2D> ();
         rend = GetComponent<SpriteRenderer> ();
         anim = GetComponent<Animator> ();
         afterimage = transform.FindChild("AfterImage").gameObject;
     }
 
 void Update ()
 {
         anim.SetFloat("verticalSpeed", r2d.velocity.y);
         direction = 0.0f;
 
         if (isGrounded)
         {
             anim.SetInteger ("state", 0); // Idle
         }
         else
         {
             anim.SetInteger ("state", 3); // Fall
         }
         anim.SetBool("isGrounded",isGrounded);
 
         if (!isBackDashing)
         {
             if (Input.GetKey(KeyCode.RightArrow))                         //Move Right
             {
                 rend.flipX = false;          // Face Right
                 anim.SetInteger("state", 1); // Walk
                 direction = 1.0f;            // To The Right
             }
             
             if (Input.GetKey(KeyCode.LeftArrow))                          //Move Left
             {
                 rend.flipX = true;           // Face Left
                 anim.SetInteger("state", 1); // Walk
                 direction = -1.0f;           // To The Left
             }
             
             if (Input.GetKey(KeyCode.DownArrow) && isGrounded)            //Crouch/Duck
             {
                 direction = 0.0f;            // Stop And
                 anim.SetInteger("state", 2); // Duck
             }
             
                   if (Input.GetKey(KeyCode.UpArrow))                      //Cast
                   {
                           //Blank
                   }
         }
 
         if (Input.GetKeyDown(KeyCode.Z)                            //Jump
             && isGrounded && anim.GetInteger("state") != 2)
         {
             if (isBackDashing)
             {
                 isBackDashing = false;
                 afterimage.SetActive(false);
             }
             r2d.velocity = new Vector2(r2d.velocity.x,jumpHeight);
 
             anim.SetInteger("state", 3); // Jump
             anim.SetBool("isGrounded",isGrounded);
         }
 
         if (Input.GetKeyDown(KeyCode.A)                         //BackDash
             && isGrounded && !isBackDashing)
         {
             isBackDashing = true;
             afterimage.SetActive(true);
         }
 
         if (isBackDashing)
         {
             if (rend.flipX)
             {
                 r2d.velocity = new Vector2(backDashSpeed,r2d.velocity.y);
                 anim.SetInteger("state", 4);
             }
             else
             {
                 r2d.velocity = new Vector2(-backDashSpeed,r2d.velocity.y);
                 anim.SetInteger("state", 4);
             }
         }
         else
         {
             r2d.velocity = new Vector2(direction * walkSpeed,r2d.velocity.y);
         }
 }