I got 2048 block, but I see "$v" instead of value.

    _game.target_value_reached.connect ((s, v) => {
      if (_settings.get_boolean ("do-congrat")) {
        string message = @_("You have obtained the $v tile");
        _congrats_message.set_text (message);
        _congrats_dialog.present ();
        _settings.set_boolean ("do-congrat", false);
      }
      debug ("target value reached");
    });

Probably it should be something like _(@"You have obtained the $v tile");

I'm not expert in Vala.