When deciding actions it is a bit jarring that the "confirm and end my turn" button is hidden.
- The "restart turn" button can be clicked at any time.
- The "restart turn" button is centered in the button area.
- Only when the final cube is placed is the "confirm and end my turn" button visible.
More than once my memory of the screen has led me to hit confirm by accident. Every occurrence has been due to using the restart button several times before the last cube followed by trying to hit the same area after the last cube was placed.
Please consider using disabled buttons over hidden buttons.