Bruce Willis plays a character who travels back in time and at the end of the movie, dies in front of his younger self.
Bruce Willis' outfit at the end of this film is identical to his outfit at the end of Pulp Fiction. In addition, both films feature Willis' character returning to his apartment and just missing the hitmen waiting for him.
In addition, when robbing a store for medical supplies he finally gets the aspirin he was asking for throughout Die Hard with a Vengeance.
Garret Dillahunt plays Jesse, a man who works for an organization that kills people who come from the future. In The Sarah Connor Chronicles, he plays Cromartie, a character who goes back in time to kill people. Both characters are killed by a child that will supposedly be important in the future.
In the Disney live action film The Kid, Bruce Willis is confronted by his much younger past self. Obviously, that movie was a little more family-friendly.
Ad Lib: A very large, meta example with the plot; due to budget constraints around filming in France, the 2074 setting was restricted to either Shanghai or New Orleans as both were cheaper and easier, and China was chosen on the fly. Even notable with Joe learning french for no real reason, before it's lampshaded through a Creator In-Joke where Abe is really insistent Joe go to China instead, resulting in him changing his mind about France.
Reality Subtext: The scene where Abe tells Young Joe he should go to China instead of France actually mirrors the production of the film, in which Joe was going to go to Paris with his gold until the filmmakers learned how much they could get in tax credits and crack the Chinese market if they filmed in Shanghai instead.
Throw It In: Kid Blue drops his gun while twirling it, which fits with the whole "previously shot himself in the foot" gag; however, it was the only take where Segan messed up, but it was kept in because it was too funny and fitting to leave out.
One of the deleted scenes features Jesse, the gat man send to check the farm out, and Sara exploring the basement reached by the door under the stairs before cutting to the escape tunnel starting from there. It was cut for pacing, but they fortunately had a take where the actors forgot to walk back into the room while exploring the noise, which allowed changing the scene to instead involve the secret passage starting from that door.