Just a quick clip of Unreal Engine running in Firefox without any special plugins!
See it yourself here : http://www.unrealengine.com/en/news/epic_games_releases_epic_citadel_on_the_web/
"Epic Citadel" is built using standards-based technologies like HTML5, WebGL and JavaScript, and should work in any standards-based browser implementing those features. For optimal performance, Epic recommends loading "Epic Citadel" at http://www.unrealengine.com/html5 using Firefox Nightly version 23 or above, which includes optimizations for asm.js, a highly-optimizable subset of JavaScript pioneered by Mozilla, whose performance can rival native code.
