Continuity mistake: When John first meets Marcus in the cemetery, John's umbrella changes from a standard 8 rib when lowering the coffin, then a 22 rib close up, then back to 8 ribs in a far shot of the two men shaking hands. (00:04:15 - 00:05:45)
Continuity mistake: The first time John's alarm goes off at 0600, it is early moments of dawn. A little while later in the movie we see John being woken up by the puppy at 0600 and it is brighter, almost mid morning kind of light. (00:01:35 - 00:07:50)
Continuity mistake: As John gets up in the night near the start, the clock reads 1:41. As he is physically getting out of bed it reads 10:00. (00:12:40)
Continuity mistake: Just when John Wick puts the bracelet on the night table next to the phone near the start of the film, the time changes all of a sudden from 8 to 10. (00:04:00)
Continuity mistake: When John's friend enters the room where he is killed he removes his sport coat. When he is tortured and sitting in a chair, his coat is back on.
Continuity mistake: In the night club, when John is fighting the last guy before leaving, the guy throws John, he lands on his back, and has no gun/holster in his waist band on his back. A few seconds later a small pistol and holder appears and he takes it out and shoots at the other guy.
Continuity mistake: After subduing one of the henchmen at his house, John sees another one come behind his staircase's side glass pane. He shoots the henchman, putting a bullet through the glass. The shot changes to him finishing the henchman, but when the shot goes back to the stairs seconds later, the bullet hole has disappeared from the glass. (00:29:55)
Continuity mistake: The bullet hole from Marcus' shot at John's pillow disappears when he rolls over the bed. (00:55:20)
Continuity mistake: John stabs a guy below the chin and we see his hand get blood on it in a closeup. Next shot he pulls the knife against another guy, and his hand and shirt sleeve are perfectly clean. (00:49:30)
Continuity mistake: In the compound shootout, the one SUV gets riddled with bullets including a very distinctive double bullethole in one of the door pillars. This unique damage disappears a few shots later. (01:02:40)
Continuity mistake: The holes that Ms. Perkins puts into the glass above John's bed keep disappearing and reappearing. This is not to be confused with the extra bullet hole mistake already listed. (00:55:50)
Continuity mistake: John is thrown off the balcony in the red circle. When he lands, he doesn't have a gun in his belt at the back, but he then magically pulls one out a few seconds later. (00:50:30)
Continuity mistake: At the end, John pulls the knife out of his side and it's got blood on it. Camera shows him starting to thrust the knife into Viggo and the blood has disappeared. (01:27:40)
Continuity mistake: Once John has been knocked to the floor in the compound scene, he has his hand next to his face. Camera changes and it's further away. (01:03:50)
Continuity mistake: In the red circle, John stabs a guy in the shoulder before shooting him. When he shoots him however the knife has disappeared. (00:48:40)
Continuity mistake: When John is going to bed with Daisy for the first time, the clock says 10:50. John puts a pillow on the floor and now the clock's showing 10:54. (00:08:30)
Continuity mistake: At the end, John pulls out alongside the two trucks. Camera changes and now he's back in a single line behind the trucks. (01:22:34)
Continuity mistake: Ms Perkins fires her 1st shot into the 1st pane of glass, the second shot into the middle of the middle pane of glass. When the shot changes to John rolling off the bed, there are 3 holes in the glass before she fires her 3rd round. (00:55:50)
Continuity mistake: The SUV that rams into John in the compound changes from a Ford to Chevrolet. (01:03:00)
Continuity mistake: John opens the envelope that comes with the dog and it's a standard pointy envelope flap. When the shot changes it's now a horizontal flap envelope. (00:06:50)
Answer: No. Regardless of any cancellation that Viggo made after-the-fact, the "Cardinal Rule" still applies to Marcus. He accepted the contract, he was contractually-obligated to kill John Wick, and he failed to kill John Wick. Marcus broke his word, essentially, which was an inexcusable violation.
Charles Miller