Hello!
I'm stuck in level four... I climb up the wall and the I fall down through the roof but after that I can't understand what I'm supposed to do... can anyone please help me?

Go into the basement and push the block to activate the gears. Then go into the room above with the other gears and pull the little stub block with the air vent thing on top to set against the gears. Now the switches work and fiddle with them until you get the statue to go through the gate and ring the bell in the next building. Then you'll meet an old lady who'll give a key. Use this key to gain access to the locked room down where the clock on the ground is. Play on from there and you'll beat the level eventually.