But I'd like to remind that I have said that the overweight landing is always not recommended, and I haven't said that it's impossible ...
Captain87,
no one is going to perform an overweight landing if it is not strictly necessary. If you get into a critical condition which does not revert into an out of critical condition, you have no choice : you MUST land as soon as possible. Critical conditions are part of another subject that has already been covered a few posts earlier. A properly executed overweight landing will cause no big damages to the airplane.