These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ken Castle is a billionaire technology magnate in a dystopian future. He develops an indulge-every-depravity-you-want-short-of-murder game called Society using brainwashed, destitute people as the players' avatars. His second game, Slayers, is a death match where condemned prisoners have to kill each other in an enclosed warzone. If they're running low on participants, Castle will frame them if necessary. If a prisoner can survive 30 rounds they'll be released, but he has no intention of honoring this arrangement and plans to kill anyone who makes it that far. He ultimately wants to brainwash most of the planet to be his slaves and rob them of anything even resembling free will. He takes over Kable's body to force him to slit his little girl's throat. Completely lacking empathy for anyone, he sees people mostly as toys to play with and destroy as he sees fit.
Hackman is an enormous inmate in Kable's prison who went on a massive killing spree just so he could be locked up and personally participate in the carnage in Slayers. He arranges with Castle to remove the mind control on himself so he has an advantage over the other prisoners and can kill Kable himself. He kills another prisoner for no reason than to show Kable the resulting blood on his hands, and threatens to kill and/or rape Kable's wife and daughter. Through the rest of the film, while working with Castle, Hackman just keeps murdering people (especially innocents) left and right, clearly deriving sadistic joy from all the crimes he commits with his own hands.
Designated Hero: It's a little hard to root for Kable when he's just as willing to mindlessly slaughter people outside of being mind-controlled as inside. A key moment is when he kills Rick Rape (or rather, whichever poor bastard the guy with the "Rick Rape" screenname is pupeetering) by snapping his spine, even though "Rick" is just as much a victim of the Society programming as Kable's wife.
You could explore how government might legislate what you're allowed to do with somebody else's bodies; after all, a contract selling yourself into slavery is not a legal, binding contract in most countries. What changed in the culture that would even allow such a thing? Or is it an illegal service, like prostitution, that is available in the darker corners of the populace?
You could explore what happens to a society when poor people are timesharing their bodies with the rich. What you have here is the very personification of the wealthy fucking the lower classes, that concept made manifest.
What about the disabled? Would you get a lot of crippled people taking other people's bodies just to experience walking again? Would the blind be able to see through someone else's eyes?
The possibilities are endless. So what do they do with it? Stage a bunch of hyperactively-edited action sequences, which ultimately ends in a villain who's too stupid to live.
Same goes with "Slayers", the game that the movie focuses on before shifting attention over to something else. It would be better to know a little bit more about the game.