Your menu works for me in IE 10, and 9, it is IE 8 and lower that don't work
So the real problem is that the media query is not working In IE. Media queries are not supported in IE 8 and lower because they are from the CSS3 standard which was adopted with IE 9./
See this page for details:
http://cssmatter.com/blog/ie7-and-ie8-support-for-css3-media-query/