When Max is watching the home recording of Melissa, the time and date are displayed in the corner. The time never changes, even though Max watches for longer than a full minute.
When he goes back to his time line at the end of the movie, his wife acts like she has no idea why he is so emotional to see them. In reality, she would have remembered that his "future" self had gone back in time to save her and her unborn child.
At the end of the movie, Walker is surprised when his son comes out to greet him as he arrives home. Since the time-line had been altered in the final showdown with McComb, he should have known that he had a son.
At the end, when the C4 is set at 2:18, it goes for more than 30 seconds longer before exploding.
When Melissa kisses Max in the mall at the beginning of the movie, she holds him around the shoulders. In the next shot she is holding him around the neck.
The Senate meeting discussing the formation of the TEC takes place in October 1994. Later that day, Walker meets his wife at the mall, where there is a display of the "New 1994 Model" Nissans. In October of 1994, Nissan would have been rolling out the 1995 models.
A major plot point to the movie is that "the same matter cannot occupy the same space". According to the tagline, Max's wife was murdered 10 years prior. Over 10 years, the human body does not contain much of the same matter it did when it started. Especially since the body is approximately 72% water, which is constantly being replenished. Add to this the food which is consumed that contributes to cell repairs, and very little "old mass" remains. Hence when Max throws the Senator at himself at the conclusion of the movie, nothing should have happened, other than the Senators bouncing off each other.
At 58:43, when the protagonists are standing in front of a monitor viewing what is described as "T.E.C. Internal Power Demand" for the Maryland facility, the units on the screen are listed as "in TERRA WATTS (TW)" instead of Tera Watts.
When McComb travels back in time to the factory to prevent the deal he made 10 years earlier from happening, Walker kicked him in the face. The scar on the face then appears on the future McComb; this suggests events that happen in the past alter the future.
Yet when past/future McComb touch and are therefore destroyed, the future is not changed. Because past McComb no longer exists, the future events would never happen and the entire house scene would not occur at all. This entire scene makes no logical sense because of this.
During the Senate meeting to discuss establishing the TEC, reference is made to the 1863 gold bullion, stamped "Confederate States of America" and date verified using carbon dating. But carbon isotope ratios cannot be used to date gold bullion because there is too little carbon present in bullion to measure.
In the fight scene at the end in the attic, Van Damme's double can be clearly seen when kicking the intruder down the stairs.
At one point there is an effects shot in which Senator McComb walks round his earlier self. There is a strong raking light coming from screen right throwing strong shadows down the (screen) right hand sides of both versions of the actor. Yet, as the actor walks 'past' - i.e. between the earlier version of himself and the light source - no shadow falls on the stationary actor as it would have done if someone had really walked past him with that lighting.
When Walker visits Fielding in the hospital, she asks, "Why did you come back?" There is no reason for her to have assumed that he went to the present and then returned. Since he was already there when she was shot, she would have assumed that he had stayed.
When Max & his wife have their picture taken in the mall, they are in the mall standing in front of an A&W but when Max looks at the photo after returning from the Atwood mission it shows them out on a street.
The film's time travel rules make no sense at all. They say that one cannot go forward because the future has not happened yet, but they say that you can go back. This is ludicrous because when they return to their own time they are indeed going forward. If you can go back then you can go forward. If what they said were indeed true then the travelers would be stuck once they go back.
When Walker's ex-partner Atwood is shown in 1929, a fight breaks out in the office and a lamp is broken. The lamp has a frosted light bulb. Frosted Light Bulbs weren't invented until many years later.
At 22 minutes and 44 seconds during the jump from the building in the 1929, the reflection of a modern building called the 'Harbour Centre' can be seen in one of the windows. The 'Harbour Centre' is a building located in Vancouver, B.C., Canada, not New York City. Further, the 'Harbour Centre' was opened in 1977.
In the opening scene set in 1863, a horse-drawn carriage can clearly be seeing being drawn down a country track made by modern vehicle tyres.
When Walker is in the Parker/McComb warehouse he pulls back his gun to put a bullet in the chamber but when he does there's no sound.
At ca. 1:28:54, a crewman is visible walking into the burning building after the C4 goes off.
When McComb returns to the 2004 where he is rich and winning the election by a landslide, his assistant still has the nose injury he got before the timeline was changed. This injury was specifically caused because of McComb's frustration with the events he then changed, so it shouldn't exist in this new timeline.
The characters repeatedly state that "the same matter cannot occupy the same space" when time traveling, which means that time travelers cannot physically touch past versions of themselves without suffering fatal consequences. The problem with this logic is that this would not result in matter "occupying the same space", because it is physically impossible for this to actually happen. When two people touch each other, they are not occupying the same space - they are just very close to each other. But no matter how close two people can get, the atoms that make up their physical bodies will never occupy the same space as one another.
History was altered when General Lee's gold shipment was stolen to be used for an arms deal. However, this didn't seem to have impacted present day. The original time line had been overwritten and would have affected the future.
Walker's job is to prevent people using time-travel to alter the past, thereby changing the future; this is what he's trying to prevent McComb, the film's main antagonist, from achieving. However, when Walker himself travels through time, he does not hesitate to cause as much damage to his surroundings as humanly possible. When he travels back to 1928, for example, he beats up two security guards, fires a futuristic laser-cannon in front of a large crowd of people, then jumps out of a window with the criminal in tow, and disappears into a wormhole above a busy street in New York City. Doing these things would drastically alter history, but none of these events seem to have any noticeable effect on the future/present.
When Walker returns to the present, there should be two of him, since his former self would not have had a reason to travel back to when McComb tried to murder him and his wife, sort of like in Deja Vu with Denzel Washington.
In the beginning of the movie when George Spota is talking to the senate committee he states that an arms deal was being paid for by gold bullion from the civil war. He states that this coin was carbon dated back to that time. This cannot be so for two reasons. One if it was brought forward in time it would not have had a chance to age. But even more so is that you cannot carbon date metals. Carbon dating can only be used for organic matter, material that was once living.
When Agent Sarah Fielding gets shot by the 2004 Senator McComb in 1994, she lives and is taken to the hospital. Shortly thereafter, Agent Max Walker returns to 2004 to discover that his agency the TEC has no record of an Agent Sarah Fielding in their computer system. The Sarah Fielding who was shot and incapacitated was the Sarah Fielding from their time 2004, not 1994. The younger teenage Sarah Fielding had not been shot in 1994. She would have lived to 2004 and she would have joined the TEC only to be shot once she went back to 1994.
At the beginning of the film, when the time traveler asks the Confederate soldiers to give him the gold, one of the soldiers repeatedly refers to him as "y'all." No actual Southerner would use "y'all" as a singular; it is uniformly plural.