,Hello,
I have a good background with Cocos2d-x (in JavaScript and C++). If I understood correctly, you have a platform (tmx format) on which you want the player to be able to move left, right and jump. Also, you want to player to fall at the end of the platform, but not die.
If you want to work with me, we need to discuss first the exact details in order to be sure that we have the same thing in mind.
Thanks,
Paul