Automatic menu generation by articles and categories structure (this menu does not exist in Joomla "Menu" backend section)
Showing categories with link to index article
Searching categories' index articles by customizable regular expression
Categories and articles ordering control
Full CSS control of displaying menu: a LOT of various classes assigned to menu items
Customizable filtering features:
-- Filtering by atricles/categories published/unpublished status
-- Root node visibility customizing
-- Category query depth option
-- Ablility to union top levels of menu
-- Ability to hide some menu levels parent of child to selected
-- Hiding by CSS of removing hidden menu items
-- Hiding items in not selected branches
-- Controlling behavior of hiding nodes if no one selected
-- and the others!
-- This menu shows as select element (styled with JS and CSS, but it may be turned of). User jumps to according page when selects an item.