Not sure if it has already been discussed, but I think that this piece of code in CCDirector.cpp :
// If we are debugging our code, prevent big delta time
if (_deltaTime > 0.2f)
_deltaTime = 1 / 60.0f;
should be removed or at least clearly mentioned somewhere in the documentation.
This is really a huge difference between DEBUG and RELEASE mode and caused me a lot of troubles when I switched to release mode.
In fact, in my game, I'm doing simple physics calculations which I tested for a long time in debug mode. When I finally switched to release I got some inexplicable glitches taking a lot of time to fix... without that piece of code I would have found those bugs ages ago