6. Zero (by Lester Smith and Steve Stone; published by Archangel Entertainment in 1997)
The characters are rebels who have been expelled from a telepathic hive. Think of it as waking up in the Matrix movie. Each character is part of a caste (or was): archivist, breeder, drone, soldier, or tech. Abilities are like skills, but separated into focus abilities (expert), prior abilities (rusty), and unfamiliar abilities (unskilled). The total number of focus abilities is the focus rating.
Interesting stuff... Matrix came out in 1999, like 13th floor; Dark city is from 1998.
Apparently, a common theme at the time. Curiously, the whole thing faded out... even as we get closer and closer to achieving instruments that might allow us to experience a simulation (and progressively stranger times, like 2020...).