A couple of articles that might interest y'all:
- Three.js + ImpactJS = 2.5d platforming (http://www.html5gamedevelopment.com/html5-demos/2012-08-threejs-+-impactjs--crazy-cool)
- Impact++ (http://www.html5gamedevelopment.com/html5-demos/2013-03-impact++), an extension to ImpactJS allowing lighting effects and more
- Popular mobile game Doodle Jump rewritten in HTML5 (http://cssdeck.com/labs/html5-doodle-jump)!
I do believe a bar has now been raised for game development using JavaScript!