This may not be Argento's best flick but it's definitely one of his craziest.  The last twenty minutes especially -- the world's longest telephone cord, the pool of maggot-ridden corpses, the guy breaking his thumb to get out of the cuffs, Daria Nicolodi doing a sheet metal decap, the monkey with the razor, the deformed monster kid eaten alive by flies...pure craziness, I loved it!