Continuity mistake: In the scene where David jumps to a glacier and is hit head-on with a pick-up by Griffin, they then jump into the middle of a guerilla war. The pick-up crashes and a driver is seen at the wheel beside Griffin. The shot changes to wider and when Griffin is seen exiting the car, the driver has disappeared. (01:12:30)
Continuity mistake: When David is in Egypt when the other Jumper returns from swimming, David's shirt has drops of water. Later in one shot, the drops are there and suddenly they disappear.
Continuity mistake: The lead character wears a grey waffle crew neck shirt. It gets wet and has obvious and poorly executed water spots for way too long after they jump to Tokyo. Then when he is jumping back and forth, three huge holes appear and disappear in the next jump, and the breakdown on the costume goes from heavy to none to medium. It looks like they edited sequences out of the order in which they shot them, because no wardrobe mistress could make such huge errors.
Continuity mistake: In the coliseum, Griffin breaks off the hand of a statue with his bat then picks it up and holds it in his right hand while the bat is in his left. When he jumps backwards, the bat is in his right hand but the statue's hand is gone. Griffin jumps in front of David and throws the statue's hand from his right hand and switches the bat from his left hand to his right.
Continuity mistake: Just before David has the fight in the bar, the drunk guy has his arm around him. The shot changes and suddenly his hands are by his sides.
Continuity mistake: Considering the speed and direction the cab was travelling at when they pull up in the Colosseum parking lot, there doesn't appear to be a reasonable point of entry. Following the scene, it seems as if the cab must have driven over a grass verge and through a group of tourists.
Continuity mistake: David's yellow backpack disappears right before he falls on the frozen lake. He was wearing it just a second before, when he showed the snow globe. (00:03:20)
Continuity mistake: Just after David traps Griffen in the power lines he unsheathes his knife. Then he jumps back to Millie's house and he unsheathes his knife again.
Answer: In the novel that this movie was based on, his mother was killed and David does go looking for the man who did it. Those doing the summaries are just confusing the two different versions.