Yeah, and tough luck if you're on XP I guess, you're forced to switch browser!
XP is about a decade old now. I think its completely reasonable for a web app showcasing modern technologies to not even acknowledge it's existence, let alone support it.
Modern technologies you are talking about? What I consider modern technologies are modern FPS games, like Crysis, Metro, Dirt or Rage. Cut the Rope uses techniques that are dated at least 10 years. It's a shame that people think of it as anything modern. XP can run a lot of games that are orders of magnitude more complex than any HTML5 game.
Those who downvoted you won't be happy until we've devolved into playing Zork-like text adventures and using Lynx. HTML5 will become like Flash/Silverlight ;)