It is also made clear that all of the heinous violence and torture that the character employed on his quest for vengeance were a result of the AI taking over (granting him fighting skills the character himself never had), forming a sort of partnership. But over time, it's also made clear that the AI is asserting more and more decision-making power, and near the end, you get to the point where you can never be sure which of "Grey's" choices are fully his. In retrospect, it makes his robotic kung fu look less awesome and more like a meat puppet being pushed to gruesome murder by a soulless piece of machinery.
Just before the credits roll, the AI takes over Grey's body completely, but he never notices it (his consciousness is given a perfect reality to live in), much like you wouldn't notice if a parasite started to slowly eat your brain until there was no more of you left to notice. The RoboCop movies always end with the heroic Murphy overcoming the programming and reasserting his humanity. It's a more upbeat ending, but Upgrade asks a more challenging question: If super intelligent machines took over, would we even notice?