RobotController.cs

using UnityEngine;
using System.Collections;
using System.Diagnostics;

public class RobotController : MonoBehaviour
{
    //This will be our maximum speed as we will always be multiplying by 1
    public static float maxSpeed = 9f;
    //a boolean value to represent whether we are facing left or not
    bool facingLeft = true;
    //a value to represent our Animator
    Animator anim;
    // Use this for initialization
    //to check ground and to have a jumpforce we can change in the editor
    bool grounded;
    public Transform groundCheck;
    float groundRadius = 0.2f;
    public LayerMask whatIsGround;
    public float jumpForce = 450;
    
    private Rigidbody myRigidbody;

    private float canJump = 0f;

    private void Starting()
    {
        this.myRigidbody = this.GetComponent<Rigidbody>();
    }
    void Start()
    {
        //set anim to our animator
        anim = GetComponent<Animator>();

    }
    
    // Update is called once per frame (dependent on fps), FixedUpdate is used when dealing with Rigidbody (every fixed frame)
    void FixedUpdate()
    {
        grounded = false;
        //set our vSpeed
        anim.SetFloat("vSpeed", this.GetComponent<Rigidbody2D>().velocity.y);
        //set our grounded bool
        grounded = Physics2D.OverlapCircle(groundCheck.position, groundRadius, whatIsGround);
        //set ground in our Animator to match grounded

        anim.SetBool("Ground", grounded);

        float move = Input.GetAxis("Horizontal1");//Gives us of one if we are moving via the arrow keys
                                                 //move our Players rigidbody


        this.GetComponent<Rigidbody2D>().velocity = new Vector3(move * maxSpeed, this.GetComponent<Rigidbody2D>().velocity.y);
        //set our speed
        anim.SetFloat("Speed", Mathf.Abs(move));
        //if we are moving left but not facing left flip, and vice versa
        if (move < 0 && !facingLeft)
        {
            Flip();
        }
        else if (move > 0 && facingLeft)
        {
            Flip();
        }

        if (grounded && Input.GetKeyDown(KeyCode.UpArrow) && Time.time > canJump)
        {
            this.GetComponent<Rigidbody2D>().AddForce(new Vector2(0, jumpForce));
            anim.SetBool("Ground", false);
            canJump = Time.time + 1.25f;
            //grounded = false;
        }
    }

    public virtual void ComputeVelocity()
    {

    }
    void Update()
    {

    }
    //flip if needed
    void Flip()
    {
        facingLeft = !facingLeft;
        Vector3 theScale = transform.localScale;
        theScale.x *= -1;
        transform.localScale = theScale;
    }
}

This script, which is attached to the first player, allows them to move via the "Horizontal1" axis defined in the Input Manager settings. Thus, they are able to move using the arrow keys, and the void Flip method allows the character to constantly face the direction in which they are moving.