課題でダッシュゲームの作成、どこを改善すればいいかわからない。

前提・実現したいこと

課題で参考資料のpdfを基に、HTMLファイルとfunction.jsファイルを改変しダッシュゲームを作成する。
ローカルへfunctions.jsファイルを作成し読み込むよう改変する。
ローカルで動作するか確認する。

発生している問題・エラーメッセージ

以下がhtmlのpdfとfunction.jsのpdfの文で、どこをどう直せばいいかわからないです。
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>ダッシュゲーム</title>
  </head>
  <body>
    <canvas id="c1" width="480px" height="320px"></canvas>
    <script src="functions.js"></script>
    <script type="text/javascript">
      var files_name ="hero.png,bg.png,floor.png";
      img_url = "http://wuah.sakura.ne.jp.lesson/"

      var btn_click = 0;

      var score = 0;

      var movespeed = 10;
      var speed_adjust = 2;
      var max_speed = 32;
      var move_px = 0;
      var position_now = 0;
      var tmp_ground = 0;
      var speedup_span = 0;

      var ground_line;

      var ground_data = "260,260,260,260,260,260,260,260,260,260,0,0,0,240,240,240,240,240,0,0,0,280,280,280,0,0,0,0,0,260,260,260,260,260,260,260,0,0,220,220,220,220,220,220,220,0,0,0,0,0,260,260,260,260,260,0,0,260,260,260,260,260,0,0,260,260,260,260,260,0,0";

      var player_x = 32;
      var player_width = 32;
      var player_height = 32;
      var player_anime = 0;
      var player_anime_span = 0;
      var jump_state = 0;
      var jump_max = 36;
      var jump_minus = 2;
      var jump_now = jump_max;
      var gravity = 6;
      var player_line = 260;

      function start(){
        ground_line = ground_data.split(',');
      }

      function btnClickStart(event){
        if(jump_state == 0){
          btn_click = 1;
        }
      }

      function btnClickOut(){
        btn_click = 0;
      }

      function update(ctx){
        if(btn_click == 1){
          jump_now -= jump_minus;

          if(jump_now > 0){
            player_line -= jump_now;
          }else{
            btn_click = 0;
            jump_now = jump_max;
          }
        }else{
          jump_now = jump_max;
        }

        jump_state = 1;

        tmp_ground = 380;

        for(var x=1; x<3; x++){
          if((position_now + x)>= ground_line.length){
            var tmp_position = (position_now + x)- ground_line.length;
          }else{
            var tmp_position = (x + position_now);
          }
          if(ground_line[tmp_position]!=0){
            if(move_px !=(32 -((x - 1)*))){
              if(player_line == ground_line[tmp_psition]){
                jump_state = 0;
              }else{
                tmp_ground = ground_line[tmp_position];
              }
            }
          }
        }

        if(jump_state == 1){
          player_line += gravity;

          if(player_line > tmp_ground){
            player_line = tmp_ground
            jump_state = 0;
          }else if(player_line >= 320){
            gameover_fhg = 1;
          }
        }

        ctx.drawimage(img_obj["bg.png"],0,0,480,320,0,0,480,320);

        writeText(ctx,16"white",5,5,'SCORE;'+ score);

        for(var x=0; x<16; x++){
          if((position_now +x)>= ground_line.length){
            var tmp_position = (position_now + x) - ground_line.length;
          }else{
            var tmp_position = (x + position_now);
          }
          if(ground_line[tmp_position]!=0){
            ctx.drawImage(img_obj["floor.png"],0,0,16,48,((x*32)- move_px),(ground_line[tmp_position]-16),32,96);
          }
        }

        move_px = move_px + move_speed;
        if(move_px>32){
          move_px -= 32;
          position_now += 1;
          if(position_now >= ground_line.length){
            position_now -= ground_line.length;
          }
          score++;
          speedup_span++;
        }

        if(move_speed < max_speed){
          if(speedup_span > 100){
            move_speed += speed_adjust;
            speedup_span = 0;
          }
        }else{
          move_speed = max_speed;
        }

        ctx.drawIamge(img_obj["hero.png"],(player_anime*32),64,32,32,player_x(player_line -player_height),32,32);

        player_anime_span++;

        if(player_anime_span == 6){
          player_anime_span = 0;
          player_anime = 0;
        }else if(player_anime_span == 4){
          player_anime = 2;
        }else if(player_anime_span == 2){
          player_anime = 1;
        }
      }
    </script>
  </body>
</html>

ここから下はfunctions.jsファイルの文

var img_loaded = 0;
var img_obj = [];
var btn_X = 0;
var btn_Y = 0;

function $(id){
	return document.getElementById(id);
}

window.onload = function (){
	imageParse(files_name);
	
	document.addEventListener("mousedown",btnPush);
	
	document.addEventListener('mouseup', btnOut, false);
	
	start();
	
	renderer();
}

function imageParse(files){
	
	var file_array = files.split(",");
	for(var i = 0; i < file_array.length; i++){
		
		img_obj[file_array[i]] = new Image();
		
		img_obj[file_array[i]].src = img_url + file_array[i];
		
		img_obj[file_array[i]].onload = function (){
			img_loaded++;
		}
	}
}

function btnPush(e){
	
	var divide = $("c1").getBoundingClientRect();
	
	btn_X = (e.clientX - divide.left);
	btn_Y = (e.clientY - divide.top);
	
	btnClickStart();
}

function  btnOut(e){
	
	btnClickOut();
}

function renderer(){
	
	if(Object.keys(img_obj).length == img_loaded){
		
		var ctx = $("c1").getContext("2d");
		
		ctx.fillStyle = "#000000";
		
		ctx.fillRect(0,0,480,320);
		
		update(ctx);
	}
	
	var t = setTimeout(renderer,16);
}


function hitTest(x1,y1,r1,x2,y2,r2){
	
	var lineC = ((x2 - x1) * (x2 - x1)) + ((y2 - y1) * (y2 - y1));

	var lineAB = (r2 + r1) * (r2 + r1);

	
  if(lineAB >= lineC){
    return 1;
  }else{
    return 0;
  }
}

function writeText(ctx,size,color,x,y,text){
	
	ctx.font = size + "px 'MSPゴシック'";
	
	ctx.fillStyle = color;
	
	ctx.fillText(text, x, (y + size));
}