Plot hole: Benoit Blanc ruins on purpose the murder dinner party because, allegedly, someone is really trying to kill Miles, and he wants to warn him that it's not a game. But as we know later, Blanc is actually trying to investigate the murder of Andi Brand and he does not really think that Miles Bron is in danger. In fact he is positively convinced that everyone has motives to kill in order to protect Miles and all he wants to be on the island for is to gather clues and investigate. Cutting the game short does not serve his purpose at all, in fact it defeats it. Had he played along, both Helen and him would have had a perfect excuse to investigate. In fact it is a miracle that nobody went back to their rooms right away after that tense moment, instead of being busy with the opening investigation; you even see that they are groaning and complaining and want to leave. The movie explains away most of the other details but none about this.
Suggested correction: Blanc knew he couldn't hide Helen's identity for long. He said so at 1:15:15. His fear was justified when Duke discovered Helen's identity on the night of her arrival. In short, Blanc and Helen were on a clock.
Regardless of how little time they had left (Blanc estimated "another week", so the leak happens presumably earlier than he anticipated), ruining the dinner does not serve the purpose; gives "Andi" less time to search the rooms, which is what Blanc planned her to do.
If the game was allowed to proceed, Helen would have been forced to play along. Any behavior, other than playing along, would have been suspicious.
Plot hole: This adaptation further exacerbates the problem of previous movie and TV versions; in the novel, Jackie would make the female designated witness talk over and over pretending also to get drunk after Linnet left to go to bed. In the Ustinov version it happened too, but the diversion didn't seem to last more than a couple minutes. Same in the Suchet version. Here, Simon even provokes Jackie practically the moment his wife exits the room. There's no time whatsoever for her to change and get in bed, let alone fall asleep.
Plot hole: During the shootout with Penguin and his gang at the warehouse Batman gets shot and falls to the ground. Penguin then creeps over to the spot he fell and realises he has disappeared and is in his car behind him. It is totally impossible for Batman to just disappear and get behind them without being seen, no matter the rain or firefight, that place was lighted enough and everybody was looking that way. (01:18:00 - 01:19:15)
Plot hole: Police Commissioner Clarke told arrestee Savage he could do 10 years hard time for armed robbery or "go inside Degnan [Correctional Institute] and get me what I want [evidence of civil rights violations]." Savage had not even been officially charged with any crime (s). A police commissioner does not determine what an arrestee will be convicted of or how much time will be served upon conviction. The Civil Rights Division of the Department of Justice investigates civil rights violations. (00:06:53)
Plot hole: When Cage and his wife and mates are going to the FBI safehouse the FBI agent shoots 2 baddies two separate times whilst Cage etc. are ascending the stairs, yet they don't hear the gunshots.