Function is not refer to hotkey error or whatever it is that you mention just now.
The function is refer to the capability of the game to be able to
1) The map able to select difficulty mode, handicap, or enable/disable super weapon technology and etc etc.
As for game mode, it refer to the variety of way the game could be play such as
1) Able to play 2 type of mode, Free for all or team deathmatch.
Between, here is the list of other mod for map section.
But, it is recommend that you request review it at map resources section.
Earth-Fury, Rui, Dr Super Good, Gilles, Firelord213,