When invoked with a custom shortcut (not Alt+Tab), and that shortcut is a modifier+nonModifier as usual, pressing nonModifier again just closes Switcheroo, which can already be done with Esc.
I'd suggest one or (customizable) both of these alternative behaviors:
just like Alt+Tab, i.e. cycle on each repeated nonModifier press (in reverse order if Shift is also pressed, unless modifier is already Shift) and switch on modifier release;
immediately hide Switcheroo and switch to first non-current window; repeated nonModifier presses toggle between two MRU windows.
When invoked with a custom shortcut (not Alt+Tab), and that shortcut is a modifier+nonModifier as usual, pressing nonModifier again just closes Switcheroo, which can already be done with Esc.
I'd suggest one or (customizable) both of these alternative behaviors: