Me and my girlfriend have released our first game! using cocos2d-x (v3.4). It’s only 5MB and ofcourse it is free 
Game mechanincs are similar to flappy bird, but with improved gameplay, there is lightning (normal maps 2D), you can collect bugs and clean the cave of garbage 
here is the link for play-store:
https://play.google.com/store/apps/details?id=com.mukagames.batadventures
Twitter and facebook:
https://twitter.com/Bat_adventures
Now I want to know how to market a bit the game 