For those reloading the game...You game is saved into your Facebook Account. As long as you are logged into your FB account and allow it to save automatically (wait 30 sec after doing something before closing) then if you delete the app or move from iPhone to iPad, load new game, you will have to play through the first few floor demo's then when it gives you control of the Wheel Cog at bottom Center, open it, log into your FB account and it will ask do you want to restore your previous game. Say yes and your old game will be loaded. IF YOU KEEP Playing the new game, it WILL OVER WRITE your saved game.
All tunnels will cost $0.00 Gold so just click it when it comes up.
I no longer buy extras because they will not fix the game. Diamonds are wasted by accidently clicking buttons because there are no "Are You Sure" choices. I will NEVER buy a floor because you will eventually get that floor and they are stealing money from you. Only use Bonus Codes for every 10th floor. Do not buy Expert Workers because 77% of them will be for floors you have already filled. If they do not change the game to allow me to exchange a combo of gold and first aid kits for diamonds then when I get to the Diamond only floors, my game will be done.
I am on floor 99, still cannot get workers for 2 floors (10 workers) that are matched for 7 different floors so will not move until all floors are producing. Now have over 2 million in gold and 2 thousand first aid kits.