Mvc изменить вид ссылок

<?php
class Route{
  static function start() {
    $routes = explode('/', $_SERVER['REQUEST_URI']);
    $controller_name = $routes[1] ? $routes[1] : 'Main';
    $action_name = $routes[2] ? $routes[2] : 'index';
    $model_name = 'Model_'.$controller_name;
    $controller_name = 'Controller_'.$controller_name;
    $action_name = 'action_'.$action_name;
    $model_file = strtolower($model_name).'.php';
    $model_path = 'application/models/'.$model_file;
    if(file_exists($model_path)) {
      include 'application/models/'.$model_file;
    }
 
    $controller_file = strtolower($controller_name).'.php';
    $controller_path = 'application/controllers/'.$controller_file;
    if(file_exists($controller_path)) {
      include 'application/controllers/'.$controller_file;
    } else {
      Route::ErrorPage404();
      exit;
    }
    $controller = new $controller_name;
    $action = $action_name;
    
    if(method_exists($controller, $action)) {
      $controller->$action();
    } else {
      Route::ErrorPage404();
      
    }
    
  }
 
  static function ErrorPage404() {
    include 'application/controllers/controller_404.php';
    $r = new Controller_404;
    $r->action_index();
  }
    
}

$action_name = $routes[2] ? $routes[2] : 'index';

$action_name = !empty($_GET['act']) ? $_GET['act'] : 'index';