3 modos de mover un objeto 2D

moveScript.cs

using UnityEngine;
using System.Collections;

public class moveScript : MonoBehaviour {


	public int horizontalSpeed = 20;
	public int verticalSpeed = 20;

	private Vector3 mousePosition;
	public float moveSpeed = 0.1f;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update () {
		//float h = horizontalSpeed * Input.GetAxis("Mouse X");
		//float v = verticalSpeed * Input.GetAxis("Mouse Y");
		float v = verticalSpeed * 	Input.GetAxis("Vertical");
		float h = horizontalSpeed * Input.GetAxis("Horizontal");
		Vector3 movement = new Vector3(h,v,0);
		
		movement *= Time.deltaTime;
		

		transform.Translate(movement);

		if (Input.GetMouseButton(0)) {
			mousePosition = Input.mousePosition;
			mousePosition = Camera.main.ScreenToWorldPoint(mousePosition);
			transform.position = Vector2.Lerp(transform.position, mousePosition, moveSpeed);
		}
	}

		
}