Literally, that is. This thing actually works, but if your arms are more T-rex than Mr. Fantastic, you might find it a tad challenging.
Creator Baron von Brunk has posted a nearly four-minute video of him playing using the controller, just to prove it works. It's worth checking out just for the orchestral version of the Mario theme.
Many more pics and hints on building your own can be found at the Baron's tumblr. I'd suggest his next project be building an appropriately scaled monitor to go with it.