Great game, one problem...

Whenever I complete a level. I cannot continue to the next one, or press any of the buttons for that matter. The app "freezes" and I have to close and re-open to continue. And it happens for each completed level.
Would love to rate 5/5, but this bug kind of ruins the fun I have with the game.

Risen_Sith about Trainyard Express, v1.66