I'm playing on fairly recent Macbook pro, Mac OS 10.5.8, Firefox: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1.11) Gecko/20100701 Firefox/3.5.11, with Flash Player 10.1.53.64 Debug, and even with glitch the only thing open, my machine is spinning out, and firefox is crashing with out of memory errors. When walking around, the experience is frequently laggy, with my characters motion becoming jerky as it walks around the screen (other players have reported similiar movement issues, also happening in chrome).