This presentation uses the Unity Web Player browser plugin. Simply, this is a bit like Flash in that its not part of the browser, its an added extra.
Chrome and some other browsers have stopped supporting plugins recently.
Use a web browser that does still support plugins such as Firefox. Internet Explorer or Opera.
Watch the video and look at the gallery instead.*
*We'll be unlikely to use this technology again, favouring HTLM5/WebGL as the technology for web delivered 3d in future.