I've a problem with the assassins I really don't know what to do with them. I must use a shield or sth but how...

What assassins?

look in the guide that has been submited

I just realized what you meant by assassins. First get the flower in the area with the huge hedge type things. To do this, make a right and hit the crow on the rock at the end. Get the crow feather and use clairvoyance. You will be looking through the crow's eyes, jump over the small gate with the door you had to push open. Move cautiously and when the camera pops out of the wall stop moving. Keep doing this until you get the flower. Go to the grave yard and go up to the building in it. Burn the vines and punch down the door, go inside and get the fake rifle. Go to the place with the sniper and use your shield as soon as the laser hits you. Keep doing this to get to the building.