Poprawka-2

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

public class ButtonInput
    : MonoBehaviour, IPointerDownHandler, IPointerUpHandler
{
    SerializeField
    GameObject m_Target; // do czego wysyłać event

    float m_TargetDirection; // -1 w lewo / 1 w prawo
    float m_Direction;

    // Use this for initialization
    void Start()
    {
        m_Direction = 0.00f;
    }

    // Update is called once per frame
    void Update()
    {
        ExecuteEvents.Execute<IMovementHandler>(m_Target, null, (x, y) => x.Move(new Vector2(m_Direction, 0), false));
    }

    public void OnPointerDown(PointerEventData eventData)
    {
        m_Direction = m_TargetDirection;
    }

    public void OnPointerUp(PointerEventData eventData)
    {
        m_Direction = 0;
    }
}