What browser are you using? Try updating the browser and if it does not help, try a different one (on firefox, it seems to be working fine).
Strange, Firefox not working might be a sign that something’s wrong. My guess is that you have an embedded GPU that does not work well with WebGL. Maybe check other WebGL games or if people with the same hardware experience similar WebGL problems.
EDIT: The game is still available for download, so feel free to try the standalone version.