Seems like there are two overlapping containers holding the menu which refuses to show itself past the wrapper.
If you change height to 150px, you will see the menu alright, but the purple bar will grow. z-index isn't helping me at least, the layer with the sub-menu refuses to leave the header. The css is real strange, I think media query removal may have had other side effects. I am still looking at it, just wanted to give you a heads up.
[EDIT] - This is the easiest way I think to make the menu show up, I am just not sure about the side-effects or how it was before removal of responsive code, but the wrapper needs to be taken off unless someone has a better idea. Take a look at the video showing what i mean.