2D Character control sample for Unity

KeyInput.cs

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

public class KeyInput : MonoBehaviour {
    public float speed;

	// Use this for initialization
	void Start () {
		
	}
	
	// Update is called once per frame
	void Update () {
        if (Input.GetKey(KeyCode.UpArrow))
        {
            gameObject.transform.position = new Vector3(gameObject.transform.position.x, gameObject.transform.position.y+ speed * Time.deltaTime, gameObject.transform.position.z);
        }
        if (Input.GetKey(KeyCode.DownArrow))
        {
            gameObject.transform.position = new Vector3(gameObject.transform.position.x, gameObject.transform.position.y - speed * Time.deltaTime, gameObject.transform.position.z);
        }
        if (Input.GetKey(KeyCode.RightArrow))
        {
            gameObject.transform.position = new Vector3(gameObject.transform.position.x + speed * Time.deltaTime, gameObject.transform.position.y , gameObject.transform.position.z);
        }
        if (Input.GetKey(KeyCode.LeftArrow))
        {
            gameObject.transform.position = new Vector3(gameObject.transform.position.x - speed * Time.deltaTime, gameObject.transform.position.y, gameObject.transform.position.z);
        }

    }
}