public void levelCompleted() {
        if ( level.targets == 0 ) {
            long diff = (System.nanoTime() - start_time) / 1000000;
            JOptionPane.showMessageDialog(Game.this, 
                    "steps: " + steps + "\n" + diff + " ms.");
            
            current_level++;
            if ( current_level < 100 ) {
                try {
                    level = level_generator.generate();
                    steps = 0;
                    start_time = System.nanoTime();
                    //level.loadLevel( level_names[current_level] );
                } catch ( IOException e ) {
                    System.out.println( e.getMessage() );
                }
            } else {
                game_completed = true;
            }
            repaint();
        }
    }