In the first round Lucas is told the blue button is for him and the red button for Iris. The strap is then moved from Lucas to Cal and he should be the blue button, but Iris is told the red button is for Cal.
After Iris' attempt to escape, she returns to the room, Lambrick delivers a speech about his son and he puts his left hand on her shoulder. The next shot shows his right hand on her right shoulder.
When trying to talk Conway into drinking the alcohol, Lambrick's hands are down on the table. But in the shots from behind Lambrick, his right hand is up by his face.
When Amy is being drowned and she stops moving, Bevans pulls her head out of the water almost instantly and announces that she is dead. At that moment Amy should be just unconscious; she would have died if she had spent a longer time underwater.
When Bevans is pointing his gun at Peter to force him back into his seat, you can see that the slide of the gun is locked back, indicating the chamber is empty.
During end credits, the character "Travis" is listed twice, once portrayed by Enver Gjokaj and again by Charlie Hofheimer. Enver Gjokaj played "Lucas", a role not listed in the end credits at all.
In the first round, Lambrick asks if the players would rather electrocute themselves or another player. Lambrick makes the common mistake of saying "electrocute" instead of "shock," because "electrocution" only happens when the victim dies from the electric shock; otherwise, the person is just getting shocked. According to the dictionary, electrocution can mean shock.