It has to do with lowering the water level in another room. If you go to the Waterfall room and wait til night a code appears on the door shaped crack behind the waterfall. Input the code and inside you'll have to lower the water level. This should do this for the entire world.
At least that's what I just did and it seem to have opened them all up.
I bet every time you laugh at CJayC, he has sex and laughs back at you. ~ sonicandfffan http://www.youtube.com/user/KoldsnedLP
Koldstare is right. Until u have lowered the water level which is done on the secret door in the 'face-waterfall' place, u can't get to it. Cracking the code for the door means cracking the code for the button presses