This was my largest concern. As I'm sure C2 makes many canvas references where as a Unity export would require large amounts of api references instead.
I think with node-webkit in the next release there shouldn't be any need to use another engine anyway.
While i'm sure node-webkit is good or great. As I understand node-webkit from the website it's a desktop only solution. As it seems now performance on desktop is fantastic and it's going to get better as time goes on. As power increases and browsers improve, and as OS start increasing native-web app support(like Win8). it would strike me that packaging for for desktop isn't a long term productive future endeavour, but instead a current place holder for convenience and steam like support of distribution.
My suggestions and of course I understand the limitations. Was that Unity wasn't limited to the desktop environment. Right now that the desktop is starting to see a decline in average consumer purchases. This was replaced by the laptop and netbook market. It's now seeing a strong shift towards the tablet. While I believe that it's going a decade for this shift to become dominant factor for the average user to PC to mobile. It does eventually leave desktop support in a minority. However, I mention that I think C2 will have a very productive life in the direction it's going.
I guess part of the frustrations is the glacial pace that development of HTMl5 technology for mobile devices have hit in the last few years. For a while it seemed like there were great strides being made, but now not so much. Actually it seems like I can find comments from 2011 wondering when WebGL for mobile will be supported. Checking with current today's support(http://caniuse.com/webgl) it doesn't seem like it's coming all that soon or in anykind of realistic time. For groups trying to achieve native performance for mobile(CocoonJS, Phonegap, appmobi) it seems that they are strangely quite bursts.
Finally I'm dropping it from there as I do believe the technological limitations of the design structure between C2 and Unity would have been substantially large. However I thought to make the suggestion anyways as I only suspected the design differences rather than knowing the details.
suggestion dropped :D