Same for me. I thought it was broken, as without scrolling to the bottom of the page, the buttons are not visible and the content itself isn't clickable.

Also it isn't obvious what X and Z are supposed to do before using them (as the explanatory text is hidden slightly behind the orange bar at the bottom for me at least). When Z is selected it is unclear how to return to the previous page, as the images on the previous page aren't clickable, but the only way to exit the 'Z' screen is to click the image. Just feels a bit inconsistent, that's all.

Personally, I find the placement of the up arrow being adjacent to the left arrow but the right arrow being placed on the far right a bit jarring. I expect it to be a block of three buttons together - left arrow, up arrow, right arrow - in the centre of the menu options.

Interesting idea though - good luck!

On Chrome 26.0.1410.43 Linux, it's broken as well.

Same here, Chrome 26.0.1410.43 Linux

Busted to hell for me in Safari 5.