help please

var bgImg;
var myCar;
var bugs = [];
var bugImg;
var music;
var crashSound
var carXPos = 100;
var gameStarted = false;

function preload() {
  bgImg = loadImage("game-bg.jpg");
  bugImg = loadImage("bug.svg");
  soundFormats('mp3', 'ogg');
  music = loadSound('victory.mp3');
  crashSound = loadSound('explosion.wav')

}

function setup() {
  // put setup code here
  createCanvas(windowWidth - 10, windowHeight - 10);
  //create new car (ypos, speed)
  myCar = new Car(350, 5);

  // Create new bugs!
  for(var i = 0; i < 20; i++) {
    bugs[i] = new Bug();
  }
  //start button
  startButton = createButton("Let's Play");
  startButton.position(200, 200);
  startButton.mousePressed(startGame);
}

function startGame(){

  gameStarted = true;

   music.play();
}

function draw() {
  // put drawing code here
  background(0);

  if (gameStarted == true){
    startButton.hide();
  }

  myCar.drive();

  // Draw track
  image(bgImg, -myCar.xpos, 0, (height / bgImg.height) * bgImg.width, height);

  // Draw all the bugs
  for(var i = 0; i < bugs.length; i++) {
    bugs[i].display();
  }

  // Draw the car
  myCar.display();
}

//constructor
function Car(ypos, speed){
  this.xpos = 100;
  this.ypos = ypos;
  this.speed = speed;
  this.c = color(random(255), random(255), random(255));
}
//methods
Car.prototype.drive = function(){
  //if(keyCode == RIGHT_ARROW)
 // {
   // this.xpos = this.xpos + 5;
    //console.log('this works');
  //}

  if(keyIsPressed && keyCode == UP_ARROW && this.ypos > 0)
  {
    this.ypos = this.ypos - 15;
  }

  if(keyIsPressed && keyCode == DOWN_ARROW && this.ypos < height - 50)
  {
    this.ypos = this.ypos + 15;
  }

  /*if(this.xpos > width)
  {
    this.xpos = 100; // start off screen
  }*/

  this.xpos = this.xpos + this.speed;

  // Collision detection!
  for(var i = 0; i < bugs.length; i++) {
    // Bug variables
    var bx = bugs[i].xpos - myCar.xpos;
    var by = bugs[i].ypos;
    var bw = bugImg.width * bugs[i].scale;
    var bh = bugImg.height * bugs[i].scale;

    // Car variables
    var cx = carXPos;
    var cy = myCar.ypos;
    var cw = 100;
    var ch = 50;

    // Check for intersection of the rectangles
    if(!(bx > cx + cw || bx + bw < cx || by > cy + ch || by + bh < cy)) {
      // Game over!
      crashSound.play();
      this.xpos = 0;
    }
  }

  //console.log('howdy');
}
Car.prototype.display = function() {
  // Draw car
  fill(this.c);
  rect(carXPos, this.ypos, 100, 50);

  //wheels
  fill(0);
  ellipse(carXPos + 20, this.ypos + 45, 30, 30);
  ellipse(carXPos + 80, this.ypos + 45, 30, 30);
}


// constructor
function Bug() {
  this.xpos = random((height / bgImg.height) * bgImg.width);
  this.ypos = random(height);
  this.scale = 0.5 + Math.random();
}
Bug.prototype.display = function() {
  // Draw bug
  image(bugImg, this.xpos - myCar.xpos, this.ypos, bugImg.width * this.scale, bugImg.height * this.scale);
}