I'm seeing the problem on a 64GB third generation iPad. If I restart the game the heros are back in the office, but since the only missions I have available at the moment at the bus missions, I kind of stuck until a non bus mission comes up.
Just started playing this and it's pretty cool, but I found a fairly significant bug. I can't seem to actually do any of the bus rescue missions. When I got to the screen and tap the Approve button I get the "Approved" stamp on screen and that is that. The only way to keep playing the game is to kill the app and restart, which still leaves me with a mission that I can't do. Two of them actually at this point in time, and since I don't have any other missions, I can't really progress.