Continuity mistake: After Hall has been shot in the leg in the simulation of LA 1937 the hole in his trousers and his injury disappear, as seen in the fight sequence at the pool. Hall even uses his leg to hit the bartender in the stomach, what would have made this very painful if he had been shot there.
The Thirteenth Floor (1999)
Ending / spoiler
Directed by: Josef Rusnak
Starring: Vincent D'Onofrio, Craig Bierko, Gretchen Mol, Armin Mueller-Stahl
Douglas Hall finds out that his world is actually another virtual reality world in itself. Whitney is killed in the 1937 L.A. virtual world which brings his 1937 counterpart into Douglas' world. The same thing happens with Douglas' future "real" world counterpart, who is killed in Douglas' world, thus Douglas and Jane live happily ever after (of course) in the "real" world. Douglas Hall did kill Fuller (at the beginning of the movie) but it was another user "inhabiting" Doug's body. Mr. Fuller is alive and well in the "real" world (the year 2030something or 2040something). In a nutshell: the 13th floor is simply a virtual reality world within a virtual reality world.
SkinRock
More mistakes in The Thirteenth Floor
Jane Fuller: I fell in love with you before I even met you.
Douglas Hall: How can you love me? I am not even real. You can't fall in love with a dream.
Jane Fuller: You're more real to me than anything I've ever known.