Continuity mistake: The Flash gets his foot frozen in the museum fight scene. The ice on his foot disappears in the shot after The Flash says "The gang's all here". (00:04:50)
Continuity mistake: When the Flash first runs into his museum, there are flames outside the door. When the scene cuts to inside, the flames are no longer there. (00:03:20)
Continuity mistake: Barry first enters his house to find it has been broken into, with the first few feet of the interior covered in glass. In the shot where he says "Mom" and the camera pans out a bit, the glass on the floor is no longer there. (00:01:40)
Continuity mistake: Just before Barry's mother notices the gas station, Barry is standing behind his mum on her left. Two shots later, Barry is suddenly standing behind his mother on her right. (00:00:50)
Continuity mistake: After Flash fixes the timeline, he is back in Bruce's Batcave and gives Bruce a letter from his father. Bruce is working at a station and his utility belt is there as he is working on it. When the camera pulls back before Flash runs off, his utility belt vanishes. (01:17:00)
Other mistake: The television news report about the battle between Captain Boomerang and Citizen Cold has a message scrolling across the bottom. The problem is that the words are moving from left to right, which forces the viewer to read the message backwards. (00:12:40)
Factual error: Batman shoots Reverse Flash in the head, and the camera pans up to show the hole through his head with Batman on the other side. The hole's entrance and exit wounds are the same size. A bullet wound would never be like that. As the bullet passes through flesh, it pushes flesh before it, making the wound bigger and bigger the deeper it goes. The exit wound is always quite a bit bigger than the entrance. The exit wound does almost appear larger from this shot, but that is just the illusion of the wound coming towards the camera. (01:12:05)
Other mistake: Cyborg confronts Batman about throwing Yo-Yo off the roof and then turns on a hologram projector in his arm to show other super heroes. There is a beam emitted from his arm generating the holographic images. We then see him turn the beam off, yet the holograms remain and they have a conversation with them. (00:17:55)
Factual error: Young Barry discovers the murder scene of his mother and stands in shock in the doorway. The light fades showing the transition from day to night and there are forensic scientists around the scene and cops analyzing it and asking people questions. Barry is still shown there at the door watching as his mother is put into a body bag. The police would not have kept him there to see that and would have taken him away to be questioned as soon as the place became a crime scene. Barry would most likely have been the one to call the police about the murder, meaning he would have had to return to that spot, so the police would have taken him away. And even if someone else called and Barry stayed in that exact same spot, trauma councilors would have been called to come and take him away for counseling. Either way, Barry would not have still been at the scene at this time. (00:01:45)
Continuity mistake: After Young Barry's mom grabs him by the shirt, the camera angle shows their broken down car by the road. A few shots later as Barry takes off running towards the gas station, the distance between the road and the car has increased by about double. The patches of grass around the car also change around between shots. (00:00:55)
Revealing mistake: When Lois Lane jumps into a trench whilst she is being chased, there is a vertical lined zip on her jacket. She turns her head partway and the vertical shaped zip on her jacket disappears for a frame or two. (00:39:10)
Continuity mistake: When Wonder Woman is sharpening her sword, the direction of the sharpener changes between shots. (00:33:45)
Continuity mistake: Barry places a bouquet of flowers on his mother's grave at the end of the movie. The bouquet is upwards to start with, but lying on the ground when the shot cuts. (01:15:25)
Continuity mistake: Aquaman coughs up blood after he is stabbed by Wonder Woman. Some blood goes on his chin. Throughout the rest of this scene, the blood on his chin keeps going from the right side to the left side of his chin. (01:10:25)
Continuity mistake: After Wonder Woman stabs Aquaman, she points the sword to Aquaman's neck. The direction of the sword changes between shots from vertical to horizontal. (01:10:20)
Continuity mistake: When Batman starts shooting at the heat vision guy, an orange car is behind him. The shot cuts and he is suddenly standing with the car on his left. (01:01:45)
Continuity mistake: Batman is blasted against a green car by the guy with heat vision. He runs to the next vehicle as the heat vision guy shoots a ray at the green car, and the next shot shows the car is now purple. (01:01:40)
Continuity mistake: When The Flash is on Batman's computer, the number of windows cracked/smashed changes between shots. (00:45:10)
Continuity mistake: Lois hides under a purple car. It becomes red after a beast walks over the bridge. (00:39:15 - 00:39:45)
Audio problem: The scene after The Flash regains his powers and saves Batman, we see Lois Lane running through a street. Her speech doesn't match what she says. (00:39:00)
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