i would simplify the site a bit. you have decent content, keep you keyword density around 30%.
One thing i highly recommend if to loose all that script you have running on the site. Only run the script that is necessary.
loose the sound effects, not needed - longer load time.
add google analytics and a google sitemap.
this will with out question get you a hight ranking.
I found some interesting stats on browser usage. Firefox now holds a 37% market share compared to 7.2% in 2003. They have done a terrific job promoting online. here are the full stats:
http://www.w3schools.com/browsers/browsers_stats.asp
I would have to agree that tat is inaccurate, because much is based on traffic (organic and paid), relevance of inbound links, code structure, site structure, among many others.