I built a demo with some similarities 7 month ago (EDIT - that's not a plagiarism charge, the OPs submission predates mine and was created a year ago). https://gist.github.com/arnehormann/4163916 for the source and http://bl.ocks.org/arnehormann/raw/4163916/keycodes.html for the demo. The code is documented and includes a konami code and a mode switching example. It's set to a German Windows keyboard layout, but the code includes comments on how to change that.