It's kind of like The Matrix, It is kind of like eXistenZ...only it is also kind of neo noir, and it is far more mystery/thriller...and it...wait, not it's actually a completely different film.
Let me start again...
It's kind of like Dark City and it's kind of like The Matrix and....no, that really doesn't fit either.
It's kind of like a lot of elements in other movies that are kind of like this one. So people are going to see similarities...but it is also going to throw them for a loop and be a lot different than the movies that you can compare it to
It's not original, it's just combined enough to be kind of completely original.
In fact, forget it, just sit down and watch it yourself, it will entertain you and that was the point of making it.
The Thirteenth Floor has an amazing premise and some great ideas. Shame that it's also mired by terrible dialogue, B-movie plotting, and a cheap looking production. Blending elements of Dark City and The Matrix though never achieving the greatness of either of those magnificent works of sci-fi, I would still recommend The Thirteenth Floor for what it sets out to do. It's also cool to see the younger versions of Gretchen Mol, Vincent D'Onofrio, and Dennis Haysbert.