Continuity mistake: After Batman shoots Reverse Flash through the head, Flash rushes over to Batman and catches him before he falls over from his wounds. As Flash is lying him down slowly, there is no blood on Batman's face. It then cuts to a close up as Batman reaches up to pull off his mask and there is suddenly blood on his lips and chin. (01:12:20)
Continuity mistake: After dodging a low attack, Wonder Woman jumps into the air and slashes down at Aquaman with her sword. Aquaman raises his trident and blocks the attack, but is only holding the trident with one hand. It cuts to a close up and instantly Aquaman is two handing the trident. (01:00:25)
Continuity mistake: After Aquaman finds Orm dead and sees the carnage of the battle, Wonder Woman comes up behind him and stabs his back with her sword. He falls to his knees and she walks around in front of him, and as she does you can see there is no blood on her sword. But then she holds the sword to his neck in a close up and suddenly the sword is covered in Aquaman's blood. (01:10:15)
Continuity mistake: When Barry is looking at the gun case in the Batcave, a cork board is visible in the background covered in raggedy playing cards. The one to the left of the center Joker card has blood on it, a lot of it around the bottom right corner of it. Later when Batman looks at the cards, the blood on that card is significantly less. There is also a card to the right of the Joker card that is torn with no blood on it. But in the close up when Batman is looking at it, that card now has a large blood spot in the center. The card symbols on the cards are also closer together, the cards above the Joker are significantly less damaged, and change from suit of hearts to a different suit. The entire board seems different. A few shots later, the cards above the Joker card are back to hearts again. (00:20:45 - 00:25:30)
Continuity mistake: When Flash, Batman, and Cyborg walk into the cell that is holding Superman, a shot of just Superman's legs show that they are down with his knees on the floor. It then cuts to an angle from the trio and suddenly his legs are bent up and his knees in the air. (00:49:35)
Continuity mistake: When Reverse Flash stabs Flash in the leg with a piece of rebar, Flash is on a small pile of rubble. He takes the bar out and drops it on the rubble. But then it cuts to a different angle as Reverse Flash continues to assault Flash, and suddenly Flash is in a different location, with no piles of rubble in his immediate area. (01:04:50)
Continuity mistake: As Cyborg is opening the door to Superman's cell, several layers of blast doors open one at a time. The last one to open you see for a moment as it begins to slide, you can see the room beyond through it in red. It then cuts to the other side and suddenly there is yet another layer of door that is opening by just sliding to the right, preventing any possibility of a view seen less than a second before. (00:49:30)
Revealing mistake: During the flashback when we see Bruce Wayne murdered, Thomas Wayne is beating up Joe Chill while in the background, Martha can be seen cradling Bruce's dead body. As she picks him up though, the animators forgot to remove the still frame so it appears as if there are two corpses.
Continuity mistake: Reverse Flash smacks Flash over to the edge of a building. The building is heavily damaged from the war and crumbling. The edge is broken off and jagged, but averages out to a straight line. A few moments later, when Reverse Flash puts his foot on Flash, the broken edge of the building has become much more jagged and uneven. (01:05:40)
Continuity mistake: While fighting Black Manta, Batman stands next to an orange car as he blasts away with his pistols. Between shots, the front seats of this car change from separate seats to a bench seat. (01:01:45)
Continuity mistake: When Barry lays flowers at his mother's grave, the base of her tombstone changes style between the close up and when he stands up and runs to his wife. (01:15:25)
Continuity mistake: Overlooking the crater left behind by Superman's ship in Metropolis, Flash and Batman are standing on the roof of a building with concrete tiles. The tiles change in size a few times during this scene, most notably bigger when Cyborg looks up at a satellite. (00:46:10)
Continuity mistake: After he gets his powers back, Flash takes off to try and time jump with speed. He fails and trips, sliding to a grinding stop out in the open desert. The shot from the side of him on the ground shows him lying on rolling "sand waves" and looks rather smooth with no vegetation around him except some cacti in the distance. The shot then cuts to an over head view as he sits up and starts to weep in desperation. Suddenly the rolling sand is now a dried cracked dirt and there are bushes and more cacti around him. (00:43:10)
Continuity mistake: The bridge Lois hides under has several impact holes on the side of it from the war. These holes change in number and position in different shots of the bridge. (00:39:35)
Continuity mistake: After fighting for a brief few seconds, Black Manta kills Deathstroke by burning a hole through his chest with his heat vision. Deathstroke falls right next to Lex Luthor as his chest sizzles and his swords fall around him to. A couple shots later as Black Manta is picking Lex up, Deathstroke's body and swords have vanished. (00:29:35)
Continuity mistake: After Wonder Woman snares Steve Trevor with the lasso and begins interrogating him, the other Amazons that were chasing him walk up in front of Wonder Woman. There are 5 Amazons there, including Wonder Woman. A few shots later when she's holding Steve up, a 6th Amazon girl suddenly appears with the other 4 that were in front of Wonder Woman, standing almost behind Wonder Woman but to the side. (00:22:40)
Continuity mistake: As Lex Luthor is discussing the shockwave epicenter with Deathstroke, he places his finger on the computer screen about an inch away from the Epicenter blip down to the left just as the orange moving blip begins going across the screen again. The orange blip makes it almost to his finger before it cuts to a close up of the screen. Now suddenly Lex's finger is much further away from the epicenter blip and sliding to the right, with the orange blip in front of his finger. (00:26:40)
Continuity mistake: When Flash takes off running in the desert trying to test if he can break the sound barrier, the lightning bolt on his chest is much wider than seen just a couple of shots later. (00:42:55)
Continuity mistake: While hiding from the Amazons under the bridge, Lois Lane hides by a purple car. There is an upturned blue car on the opposite side of the bridge there as well. This car disappears when the Amazons jump down to her and reappears again in the scene, also changing position a few times. (00:39:40)
Continuity mistake: Reverse Flash places a bomb on the gray adhesive substance that he has trapped Flash in next to Flash's head. From the side angle in that shot, it shows it right above his shoulder. But a couple shots later when Flash begins vibrating his arm at super speeds, the bomb is suddenly much further to the right, away from his head. (00:06:15)
Chosen answer: Despite the ending in Flashpoint to indicate a Darkseid invasion, War is not a sequel. It's a reboot. While both films were part of the DC Universe Animated Original Movies series, War is the first movie of the series that is now part of the DC Animated Movie Universe. This is also why the voice actors are different.
Bishop73