If you don't have a browser capable of handling HTML5 canvases, then you'll probably miss out on it. I recommend downloading an up-to-date browser.
As someone who is a big fan of this setting, I've noted quite a few discrepancies with the existing canon...but then again, various parts of Serenity/Firefly canon seem to conflict with each other, so I can't complain too much. I could also pick at the fact that the planets don't seem to be rotating independently around their respective suns, but since I wouldn't even know where to start on constructing something better, I'll just leave it alone.
Either way, I think it would make a great in game tool if you were setting a campaign in this oeuvre.