Most Basic 2D Character Controller

using UnityEngine;

[RequireComponent(typeof(Rigidbody2D))]
public class CharacterController2D : MonoBehaviour {

    public float speed;
    Rigidbody2D rb;

    void Start () {
        rb = GetComponent<Rigidbody2D>();
    }

    void Update ()  {
        rb.velocity = MovementInput * speed;
    }

    Vector2 MovementInput{
        get{
            int x = Input.GetKey(KeyCode.D) ? 1  :
                    Input.GetKey(KeyCode.A) ? -1 : 0;
            int y = Input.GetKey(KeyCode.W) ? 1  :
                    Input.GetKey(KeyCode.S) ? -1 : 0;

            return new Vector2(x, y);
        }
    }

    /* Published for berkinakkaya.wixsite.com/blog */
}