When Paul Kersey is at KABC radio, he is "informed" about the murder of the N.Y.C. cop in the shoot-out at Point Fermin. He was informed that five people were murdered, when in actuality, six people were murdered in the shoot-out. Those six people were the aforementioned Detective Ochoa, the blonde-haired lookout that Ochoa shoots out of a tree, the firearms dealer (old guy with suspenders and a pink shirt), the dealer's friend (wears a white cap, green shirt, and white under-shirt), Cutter, and Punkcut.
After Paul Kersey kills Charles Wilson, the hospital attendant arrives in the room. When he finds that Wilson is dead, Kersey tells him that he attacked and killed Kersey's daughter. However, Jiver actually attacked Kersey's daughter and she was never killed - she jumped out of a window to her death.
When Kersey follows Stomper into the abandoned building, a sign outside gives its name as "Motor Hotel". Later when Kersey watches the news about Stomper's demise, the reporter says it was at the "now vacant Hollywood Hotel".
When Paul Kersey is first mugged for his wallet, they are all in an outdoor market area with Spanish architecture and smaller buildings. When we see Kersey chase after Jiver and corner him in an alley, they now appear to be in a downtown location with traditional high-rise buildings.
In the scene where Kersey meets his girlfriend at the rooftop Japanese restaurant, he drinks from his glass of Dom and then puts the glass down on the table. When the shot changes he's again putting the glass down.
When we see the glass cat figurine purchased by Carol Kersey, there are two different cats used. One has a thin delicate tail, and the other has a thick sturdy tail located on the opposite side of the cat's body.
In the opening scene inside the radio station, a drop-and-pull date calendar visible through glass in an office gives the date as MAY 18 Monday. Later in the film, radio news reports indicate that the Point Fermin shootout occurred on May 14th, and courtroom testimony indicates Charles Wilson's capture occurred on May 15th.
Before Charles Bronson exits the bus after following the three thugs at approx. 58:50, he pushes the button for the bus to stop at the next stop. The bus stops and he gets off of the bus. As the camera shows the outside of the bus, there is no bus stop at that location.
In Death Wish, Kersey's daughter is married (her husband is seen with Kersey at the hospital after the attack) but in Death Wish II, no mention is made of Kersey's son-in-law. However, given that several years pass between the movies, it is possible the two separated and/or divorced sometime between films.
When Paul fires the single shot at Nirvana in the hospital, Nirvana is flipping a table up and pushing it towards him. In spite of firing directly into it, no bullet hole appears in the white tabletop.