added more sounds and autocollect coin

scripts/enemies/gumba.gd

@@ -40,7 +40,8 @@ func f_die():
 	speed = 0
 	animated_sprite_2d.play("die")
 	timer.start()
-	die.queue_free()
+	if die != null:
+		die.queue_free()
 	die_sound.play()
 	ray_cast_left_2.queue_free()
 	ray_cast_right_2.queue_free()