The Boundary tower
Ø When players reach a certain level they unlock the Boundary tower. The Boundary tower menu can be entered from the top right corner in the main screen.
Ø Players can enter the Boundary tower a limited amount of times each day.
Ø You need to pass each stage to unlock the next one.
Ø You can sweep stages that you have already passed automatically.
Ø The stages in the Boundary tower are generated at random and change every time you enter.