Continuity mistake: When Diana get the photo at the start, there's a clipboard beside the case when she opens it, but from another angle there's nothing there.
Continuity mistake: As Diana is translating in the General's office, one of the buttons on her coat is undone/missing. As she approaches his desk, it's suddenly visible on her coat where it should be.
Plot hole: How is it possible that Diana is unaware of the concept of marriage? She has a grasp of multiple languages and cultures and can recite Socrates. Socrates often spoke of marriage, so even if her people do not marry, it makes no sense that she is completely unfamiliar with this human custom.
Suggested correction: She has never seen a man either. She read about them, but never actually saw one. One might question why she doesn't understand a man if she read about them, and yet she doesn't. Same thing with marriage.
She had never seen a man, but she knew that they existed. She speaks multiple languages, despite never having met someone from any of those cultures. My point is, if she's so well versed in world cultures, how has she never heard of the concept of marriage?
Character mistake: Chief says the poison gas should be flammable because it's hydrogen-based. Hydrogen is the most common element in the universe, and there are plenty of non-flammable substances that contain hydrogen - the most notable of which being water.
Suggested correction: Hydrogen is explosive in air at concentrations greater than about 4%.
Pure hydrogen is flammable, yes. However a chemical compound that contains hydrogen would not necessarily be explosive, or even flammable. As the original mistake stated, water contains hydrogen and is not flammable. Whilst other hydrogen-containing compounds are flammable (such as hydrocarbons), the presence of hydrogen alone is not the reason for its volatility.
Continuity mistake: While the sniper is shooting at the square, Diana loses her shield with the cannon shot but few moments later she has it back again to smash the tower.
Continuity mistake: Wonder Woman is fighting the soldiers on the second floor in the village, after she retrieves her shield. Her sword goes from properly in her hand, to being held by the blade, to held by the blade upside down, but when she looks up, just before going through the window, the blade is normal again. (01:18:05)
Continuity mistake: When the picture of Diana and Steve and co. is taken in Veld, she is wearing her black cloak, but she left that and her other clothes in the trenches, on the other side of no man's land.
Suggested correction: She's in Flanders, in November, and the battle was over. It's cold, and probably worth going back to the first trench to get her cloak again, which they now have plenty of time for.
Except I seriously doubt it would still be here as poor, displaced people would likely have taken it to keep warm, like the woman and child she spoke with.
Continuity mistake: When Diana and Steve are held at gunpoint in the alley, the gun's hammer is drawn back and in the next shot it is in the resting position. (00:53:15)
Continuity mistake: When Antiope and Diana see the god killer sword, Antiope's hands are around Diana's shoulders but in the next shots they have moved.
Continuity mistake: At the beginning while Diana as a child is running among the people, a girl in gray is walking differently between shots.
Continuity mistake: After Diana crashes through the window, there are various bits of wooden debris on the floor in front of her. In a wider angle those bits have vanished.
Continuity mistake: When Steve Trevor is at the Ottoman empire, he is beside a biplane that look like a British one. In the background to his right are a series of Fokker EIIIs, the next shot he's turning to his right, just besides a Fokker... and the British biplane has disappeared. (00:24:23)
Continuity mistake: When Steve and Diana get to London, he is on her left then on her right.
Continuity mistake: At the bar while the bald guy is pointing with the gun, Diana is across the table, but in the next second she is beside the gunner.
Continuity mistake: While WW is training as an adult for the first time she uses a whip to take down an Amazon - one second later she blocks an attack with a sword she didn't have just before.
Continuity mistake: While Hippolyta is dying her hands move on Diana's body between shots.
Continuity mistake: While Hippolyta is dying, there is a sword on a bow which disappears between shots.