We have extended default WordPress menu with new settings that allow you to create nice and useful Mega Menu. Here is a quick cheatsheet on how to use it:

Megamenu Preview

When screen gets more narrow, also more links would be hidden. But those links are always available in the one drop-down which is compatible with children and megamenus of those links. Drop-down is appropriately represented for the user to be informed that there are more links in the menu.