After reading and seeing so many novels and movies that uses the same concept it is starting to get a bit boring.
Sure a world within a world within a world is a brain teaser and makes you think but to what extent toes it affect you. Well to the people who lived on a spec in Dr Seus Horton Hears a Who, their lives depended on it. In Inception and the Matrix, their perception is at stake. How one views the world is essential to his character. But in the reality we live in our perception cannot change unless we leave it, just like the main character in the matrix. Likewise, to view their world differently the characters in The Thirteenth Floor must leave their world to know what it is. The broke the set rules and drove to the end of the virtual world.
As for creating a character that is self learning like the bartender and Douglas today’s technology is approaching it rapidly. In a sense the programmers are gods without being able to grasp their true influence. As to whether one can upload themselves into a computer, when that becomes possible, the opposite will also become possible because it is a two way connection. In that way The thirteenth Floor could be interpreted a warning showing computer programs creating their own programs etc. Then the programs which are self learning can use the connection the creators established to come all the way back to the real world where ever it may exist or if it exist.