Trouble displaying two modules correctly. Both use modernizr library

Question

http://snowcoredev.co.uk/magento/

The menu and item slider seem to render correctly in full screen, but as soon as you scale down to the mobile view, the menu stops producing subcategories.

I have tried to establish which file causes the problem, and it looks like the modernizr library is at fault (removing it from the slidebar xml declaration fixes the problem, but breaks the slider obviously). I've noticed that my theme (modified 'rwd') already loads one instance of the library. I tried removing one or the other, but it removes my menu completely, or breaks the slider as mentioned before.

I'm trying to establish how to use both modules together, but I don't have any experience with modernizr, so I'm not sure how to go about it.