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 designer in a dystopian future. He develops an artificial environment called "Society" where users can remote control other people (all of whom have no control over their own body while inside and only volunteer because they need the money and feel disgusted by it) to do any depraved thing they want with their avatars short of plain murder. Then he indulges people in even that desire as well when he offers the government a solution to the prison overcrowding by creating a second game called "Slayers", in which prisoners have to fight to the death in an enclosed warzone under the control of more remote players. Any prisoner who can survive 30 rounds will supposedly be freed, but Castle reneges on this arrangement when the hero Kable is close to winning, and sets him up to be killed. His ultimate goal, revealed late in the film, is his secret extension of the mind control nanotech they use on the "characters" in the games to the general population so he will be in personal control of 100 million people in short time, and eventually make everyone in the world his slave, robbing them of anything even resembling free will. He uses this power to control Kable's body and tries to force him to slit his little girl's throat. He is utterly bereft of empathy, to the point he sees people only as things and laughs off every one of his minions who die for him.
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 enjoy 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 pay a visit to the two "whores" Kable has on the outside, namely his wife and daughter. Through the rest of the film he 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.