Near the beginning when George talks to himself in the mirror, the glass of liquid he is about to drink changes levels every time the camera angle changes.
When Mandingo is sitting on top of George you can clearly tell that he has an undershirt under his button down. When he opens the buttons of his shirt, there is nothing underneath.
When we see George intubated with an endotracheal tube, he audibly speaks to his son. Patients that are intubated cannot speak as the tube goes in between the vocal cords. It's possible to make noise if the anchoring balloon of the tube is ruptured, but then the speech will not be clear.
One of the characters states that iatrogenic illnesses caused 7,8 millions deaths in the US in a decade. In fact, iatrogenic deaths are reported to be around 225,000 annually which makes them approximately 2,2 millions in 10 years.
At the end when George breaks the window with the IV drip stand he throws it out of the window and you can see it bounce. He is supposed to be on the seventh floor.