Revealing mistake: After the flashback to when the girls first met Cece at The Brew, she looks at them through a window outside when she leaves. If you look closely at Cece's hair, you'll notice a green glow, revealing that she's on a green screen. This explains why the image of the girls through the window doesn't look quite right. Cece is also wearing a different dress.
Revealing mistake: When Nathan and Audrey are sitting at the table in The Grey Gull, the extra in the background can be seen bringing a loaded fork inches short of his mouth then fake chewing. This happens a few times before cutting to the ending credits. (00:40:05 - 00:40:55)
Revealing mistake: When the target's iPhone rings and Christopher Chance answers it, he swipes his finger across the bottom of the screen, which is the regular gesture to answer a call on the iPhone. Trouble is that we see the screen at the time, and it's not showing an incoming call, just some sort of list - he swipes his finger over nothing of any significance at all.
Revealing mistake: Except when Sonic picks up a handful and throws it in Mario's face at the start of the fight, neither character has any effect on the sandy beach around them. Sonic even runs circles around Mario at super speeds with no effect on the soft sand. (00:15:45)