When Steve chases Max/Barry/Henry/Harry (his name keeps changing) from a parking lot into and up the stairs of a building, they then exit a building onto the street at ground level.
When Steve holds the gun to Max, Max produces a gun as he lifts his right hand. He did not have a gun in his hand and did not reach anywhere to produce it. It just appeared.
When Steve and Candy gain access to the hotel room, the man touches his toothbrush to the lamp and electrocutes himself. This is impossible.
When Alcott comes home, after turning around and locking the front door he looks up to see Candice and Steve on the floor in front of the couch. He would almost definitely have noticed them before locking the door, as he was looking in that direction.
The way Jacqueline removes her first victim's watch with one hand indicates that it wasn't attached to his wrist, but laid over and tucked under his wrist.
Nobody would hang a dart board over a television, for obvious reasons.
Steve leaves the Alcott house without his shirt.
When Jacqueline and Candy are fighting, Jacqueline kicks Candy in the face but the kick is clearly six-seven inches away from her face.
It's unclear how Candy received a deep gash to her back, as when fighting with Jacqueline, the latter had no weapon capable of cutting her.