Player.cs

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

public class Player : MonoBehaviour
{
	public float speedX;
	public float accelX;
	public float decelX;
	public float gravity;
	public float groundVelY;
	
	private Vector3 velocity;
	private BoxMover boxMover;

	void Awake()
	{
		boxMover = GetComponent<BoxMover>();
	}

	void Update()
	{
		var x = Global.input.GetAxisRaw("Horizontal");
		if (Mathf.Abs(x) > 0f)
			velocity.x = Mathf.MoveTowards(velocity.x, speedX * x, Time.deltaTime * accelX);
		else
			velocity.x = Mathf.MoveTowards(velocity.x, 0f, Time.deltaTime * decelX);
		
		velocity.y += gravity * .5f * Time.deltaTime;
		
		boxMover.MoveX(velocity.x * Time.deltaTime, BoxMover.Slide.Perpendicular);
		if (!boxMover.MoveY(velocity.y * Time.deltaTime))
			velocity.y = groundVelY;
		else
			velocity.y += gravity * .5f * Time.deltaTime;
	}
}