Where does reality stop... And the game begin?
Why it is hard sci-fi
Cronenberg builds a virtual-reality system out of biological game pods that plug into a spinal port. The film commits to its own rule. Reality is decided by which level of the game you are currently on, and the audience can never be sure which level the characters are on either. The political dimension treats the games as a distribution and licensing problem with assassins on the other side, which gives the world a working economy.
Science inside it
Wet biotech as a computing substrate, neural ports, immersive simulation with no clean exit signal. The film also leans on real worries about how long-term immersion in a system erodes a users priors about what counts as base reality.
Spoiler alert
The final scene reveals that everything before was an inner game inside an outer game called transCendenZ, and the closing question, are we still in the game, is left open. The whole film is a commitment to a single rule. Once you cannot tell, you are in.