Go to the right, jump on picture and reach the right border 2 times. Get the zapper and take the battery.
Press space to destroy the balance. Go to the first room and take the battery and go to the second pictures room and press space and take the 2 battery. Now go to the first room and press space 2 times. Go to the left border and take the battery, return in the chamber room (with the bed) and press space. Go in the hole and take the 2 battry. Return in the toilet room and press 2 times space. You win \o/