I take!
With Atomic :
You can not assign yet a button to flip menu from horizontal to vertical, but you can do a menu that shows :
Vertical games
Hortizontal games
And when you select vertical games , you enter on a new menu which is vertical.
Something for horizontal.
Or
you have an option to Automatically rotate the menu , in function of the last game launched.
ex :
you are in horizontal menu , you run Donkey kong (a vertical game) , you rotate your screen , you exit the game, now back on the menu , the menu is vertical.
Now you run a horizontal game , you rotate your screen, you exit the game, now bakc on the mneu, the menu is horizontal again.
but, you can do the same thing (automatically rotate) with Mala too , if you prefer.