At Chrome Experiments there is new game written by Dominic Szablewski in ImpactJS Game Engine.
See it at: http://www.chromeexperiments.com/detail/x-type/
Game itself is available at: http://www.phoboslab.org/xtype/
For those who want to read more about game itself see blog post on Phobos Lab blog: http://www.phoboslab.org/log/2012/06/x-type-making-of
Engine page can be found: http://impactjs.com/