У вашего броузера проблема в совместимости с HTML5
from: http://www.tf2tactics.com/entry.php?13-All-Heavy-Medic-Rush-in-Badwater
Our server usually has a limit on classes, but today is a special day! The server mods aren't working today, so some of us decided to have some fun and play all heavy/medics.
"When you play this rush, turn down your speakers or you might go deaf. The sound of Sasha spinning and shooting does not cease and if one person is calling a Medic, everyone else is too. If you are unlucky enough to turn a corner and spot a few Heavies that are already spun up, the remainder of your life will look like you are entering Hyperspace."
"Quite frankly, the number of bullets wizzing through the air during a Heavy rush is astounding. You will be taking damage continually, so be ready to run. But to dominate in a Heavy rush, you must know where to find ammo. Ammo is all you need to succeed (unless your aim is terrible.) This Rush is best played on: Well because health and ammo packs litter the floor. In addition, capturing the final point
feels epic."
-ubercharged.net
http://www.ubercharged.net/2009/07/25/dealing-with-class-rushes/
http://www.tf2tactics.com/