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)
Audio problem: Winston asks John if he has returned to the fold. In this shot, the camera is over the shoulder (of Winston) and Winston's audio is overdubbed. (00:40:25)
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)
Continuity mistake: When Viggo dies, he's sat upright. As the camera changes he's now slouched over. (01:29:25)
Continuity mistake: After the fight with Ms Perkins, John grabs her under her chin and puts his gun to her head. Camera changes to her saying "f**k you" and now his hand is on her ear. (00:57:50)
Continuity mistake: Just after his dinner reservation, we see John driving over a bridge. In the aerial view we can see several cars in front of him on the bridge. However from the shot inside the car, there are no cars in front of him. (00:34:30)
Continuity mistake: John gets his nose broken by Iosef when attacked at home. However, when he buries the dog, there are no marks on his nose or face. (00:14:30)
Continuity mistake: When John is chasing the SUV's at the end, he is level with them, then a distance behind them instantly. (01:23:00)
Revealing mistake: When John finds Marcus dead on the floor, you can see Marcus is still breathing. (01:20:50)
Continuity mistake: At the start, the blood splatter on John's phone changes instantly between shots. (00:01:50)
Continuity mistake: When John goes on the short rampage with the assault rifle we see one of the henchmen climb into an SUV and floor it. It's clear by the hubcaps and rear of the SUV that it's a Ford Expedition, but the vehicle that hits the SUV into john is a Chevy Tahoe. (01:04:00)
Continuity mistake: When Viggo crashes into John's Charger, it's bent out of shape pretty badly, almost to what would be halfway to the driver's seat. Yet John is fine, and in the next shot, the car is basically too. (01:25:50)
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