currently the game allows 1 of each item to be built and 1 armor, 1 infantry and 1 air.... I am suggesting the ability to upgrade up to 2 or 3 units at same time dependent on resources in storage. ie .. 2 or 3 armor, infantry and air units at same time...this would help everyone in the game and maybe draw more to the game since so many have left....Thanks, MikeT