PlayerController.cs

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

public class PlayerController : MonoBehaviour
{
    public float moveSpeed;
    private float moveSpeedStore;
    public float speedMultiplier;
    public float speedIncreaseMilestone;
    private float speedIncreaseMilestoneStore;
    private float speedMilestoneCount;
    private float speedMilestoneCountStore;
    public float jumpForce;
    public float jumpTime;
    private float jumpTimeCounter;

    private bool stoppedJumping;
    private bool canDoubleJump;


    private Rigidbody2D myRigidbody;

    public bool grounded;
    public LayerMask whatIsGround;
    public Transform groundCheck;
    public float groundCheckRadius;

    private Animator myAnimator;

    public GameManager theGameManager;

    public AudioSource jumpSound;
    public AudioSource deathSound;


    // Start is called before the first frame update
    void Start()
    {
        myRigidbody = GetComponent<Rigidbody2D>();
        myAnimator = GetComponent<Animator>();
        jumpTimeCounter = jumpTime;

        speedMilestoneCount = speedIncreaseMilestone;
        moveSpeedStore = moveSpeed;
        speedMilestoneCountStore = speedMilestoneCount;
        speedIncreaseMilestoneStore = speedIncreaseMilestone;
        stoppedJumping = true;
    }

    // Update is called once per frame
    void Update()
    {
        grounded = Physics2D.OverlapCircle(groundCheck.position, groundCheckRadius, whatIsGround);
        myRigidbody.velocity = new Vector2(moveSpeed, myRigidbody.velocity.y);

        if (transform.position.x > speedMilestoneCount)
        {

            speedMilestoneCount += speedIncreaseMilestone;
            speedIncreaseMilestone = speedIncreaseMilestone * speedMultiplier;

            moveSpeed = moveSpeed * speedMultiplier;
        }

        // Prevent jumping when clicking UI elements
        if (Input.GetKeyDown(KeyCode.Space) || Input.GetMouseButtonDown(0))
        {
            if (EventSystem.current.IsPointerOverGameObject() && EventSystem.current.currentSelectedGameObject == null)
                return;
            if (Input.touchCount > 0 && Input.touches[0].phase == TouchPhase.Began)
            {
                if (EventSystem.current.IsPointerOverGameObject(Input.touches[0].fingerId))
                    return;
            }

            // Jumping code
            if (grounded)
            {
                myRigidbody.velocity = new Vector2(myRigidbody.velocity.x, jumpForce);
                stoppedJumping = false;
                jumpSound.Play();
            }

            if (!grounded && canDoubleJump)
            {
                myRigidbody.velocity = new Vector2(myRigidbody.velocity.x, jumpForce);
                jumpTimeCounter = jumpTime;
                canDoubleJump = false;
                stoppedJumping = false;
                jumpSound.Play();
            }

        }

        if ((Input.GetKey(KeyCode.Space) || Input.GetMouseButton(0)) && !stoppedJumping)
        {
            if (jumpTimeCounter > 0)
            {
                myRigidbody.velocity = new Vector2(myRigidbody.velocity.x, jumpForce);
                jumpTimeCounter -= Time.deltaTime;
            }
        }

        if (Input.GetKeyUp(KeyCode.Space) || Input.GetMouseButtonUp(0))
        {
            jumpTimeCounter = 0;
            stoppedJumping = true;
        }

        if (grounded)
        {
            jumpTimeCounter = jumpTime;
            canDoubleJump = true;
        }
        myAnimator.SetFloat("Speed", myRigidbody.velocity.x);
        myAnimator.SetBool("Grounded", grounded);
    }

    void OnCollisionEnter2D(Collision2D other)
    {
        if (other.gameObject.tag == "killbox")
        {
            deathSound.Play();
            theGameManager.RestartGame();
            moveSpeed = moveSpeedStore;
            speedMilestoneCount = speedMilestoneCountStore;
            speedIncreaseMilestone = speedIncreaseMilestoneStore;
        }
    }
}