I searched the forums and found
Flurry plugin - deleted,
Gameanalytics plugin - without documentation (couldn't make events and time tracking work) and
Google Analytics - basic tracking like visitors count, number of custom events triggered, average time spent on screen (did not work for me)
Is there anything else to track mainly time spent, total score, score vs. time, custom goals, user paths, tries to beat level etc.
I was thinking even about non-game related stuff, as I have ideas to use c2 in marketing but without analytics it is not possible.