Factual error: Superman begins shooting his super intense heat vision at the soldiers attacking him and the other heroes. His vision cuts boats in half, and incinerates the soldiers into ash in an instant. The lasers from his eyes are super strength, with him not yet knowing how to hold any of it back or shut it off, and it is going through the soldiers and boats. Yet the vision leaves no damage at all to the ground the soldiers were standing on, nor does it create any steam when going across the water cutting boats in half. (00:52:15)
Factual error: After Lex Luthor and Deathstroke step out onto the deck of Deathstroke's ship, Ravager and begin talking, Aquaman's sub surfaces and smacks into the Ravager and it shakes violently and lurches. Yet the crew, Lex, and Deathstroke stand perfectly still just moving their arms around a bit. An impact on a ship like that would send all people standing up falling everywhere with no balance. (00:27:10)
Factual error: When the rest of the Justice League arrive at the Flash Museum, Captain Atom vaporizes a section of the wall to allow him and some others to enter. The hole shows 3 layers to the wall, the inner wall, the outer wall, and a middle apparently metal center section. There are several circle like spots around the hole in the center part of the wall. They are all perfectly round, despite being in any given direction around the circumference of the opening. This is wrong. The circles would be caused by structural bars inserted in the layer, and they would all have been either vertical or horizontal, and thus the circles would not be circles all the way around, but changing to elongated and shorter depending on where they were on the opening. Yet all are perfectly round. This would mean that the all the bars were in all different directions and converging in the center of where Atom just happened to make the hole, which would never be the case. (00:07:05)
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)
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)
Answer: Flash couldn't travel through time later in the movie not because Zoom was alive but because Zoom was also tapping into the Speed Force, preventing Flash from gathering enough of the Speed Force to break the Time Barrier. When Flash originally went back in time it's likely because Zoom was in custody, therefore not tapping into the Speed Force at that time.