Plot hole: There are several parts of the murderer's plan that are based on pure convenience and/or against all odds, moreso than in the novel due to particular choices in the aesthetics or plot. The murderer (who can't exactly sprint around with cat-like motions) gets to the General and kills him in a gruesome manner, reaching a victim entirely in the open, with the island lacking any cover, not even a tree. Vera happens also to scream providing a diversion; unlike the book, the killer does not do anything to induce her hallucination and split the group, nor sabotages the lights creating a dimly lit environment that makes the trick more plausible.
Episode #1.3 - S1-E3
Plot hole: The killer is meant to create the perfect crime, but the angle of the shot would make obvious to any forensics examiner that it's a suicide. There is practically no possibility for a person supposedly positioned across a long dining table to kill someone else with a shot under the chin. (00:55:50)