I've just gotten the game to build and run properly after converting it from Basic to C++.
First thin I noticed is that for whatever reason the axis have been all screwed up. In AppGameKit Basic X and Z are left/right forward and backward movement. In c++ for whatever reason the Z axis was switched with the Y axis so the gravity coded for Y axis is now pilling the player left. Is there a setting you'd set in the engine to show which axis is the down axis as you do in Maya and Max, Blender and Unreal Engine?
Eisenstadt Studio: Eisenstadtstudio.com
Composers Page: Milesthatch.net