I have been developing software in C++ for 21 years.
No tool or sdk is a miracle solution.
C2 is great for making html5 games for desktop. That's why I bought it!
For developing mobile games I use other skds, and so should you for now. Maybe in 2014, mobile browsers and mobile hardware will be so powerful that html5 2d platform games will run at 60fps with very fluid movement.
You have to be flexible and learn different technologies that will do the job best for that one particular project.