Ya'll this is an Ending Discussion. It's gonna be spoilers. So.... Yeah.

First up, mechanical spoilers:

The final mission has multiple endings. You can kill/mind erase The Constant for the standard ending (albeit with or without the twist of him being alive but mind erased) or you can obtain a third and entirely different ending by picking up the serum and doing nothing for about 60 seconds. The Constant will ask if you are having second thoughts and suggest you inject yourself, at which point you can with a pull of the trigger/click of the mouse. Doing so causes The Constant to comment about how he will "take care of you now" followed by scene where 47 wakes up in a padded room.

From there, you get the story spoilers/implications:

In the traditional ending, Burnwood takes over/destroys Providence and her and 47 team up to become what I call "Benevolent Illuminati" where apparently they do the same shit Providence does but like "they're totally good guys". Whatever, apparently we're supposed to believe that deep done Diana is a good person and wants to take down Providence from the inside blah blah but she was always 47's handler. She had no problem with any of that shit until it got in her way. Seems like a stretch to be like "Oh yeah, she's totally a good person and is going to do the good thing cuz.... you're the good guy hitmans. that are good. good murder. trust us. good. you're good. it's good. GOOD."
With the alternative ending, you are actually being presented with an Easter Egg. The padded room and the line spoken by the Constant "Wake up my friend, it's a new day and you have things to do" is actually the opening to the original Hitman: Agent 47. The alternate ending suggests that the World of Assassination trilogy is actually a prequel to the original game and the events of Hitman: Agent 47 take place AFTER his second mind erasure. Of course, that doesn't quite line up with the timeline or character of Diana in the earlier games but hey, it's fun. It also creates a Zelda-like parallel dimension situation where in one world 47 kills the Constant and becomes a good guy and in the alternate world he goes back to ICA Hitman just to go through the events of the original games and.... kinda become a good guy? Hitman lore man......

Minor correction: I believe the 2000 original Hitman game has the subtitle "Codename 47" instead.

Interesting theory. But somehow I feel Hitman 3 hit its finality mark two missions before, as Agent 47 leaked the ICA files out of their data centre in Chongqing. To quote a line from the game, this game does not so much burn its bridges as blow them up with this plotpoint.

Regardless of the ending, you'll probably see at least a soft reboot whenever IO comes back to the franchise. Which probably won't happen for another 5-10 years.

@infantpipoc: i mean, the alternate ending is clearly meant to be a non-canon spoof. It's not so much a theory as it just is that - the same piece of dialogue from Codename 47 and him waking up in the same padded room. Does it make sense? No, of course not, again as 47's relationship with Diana and the timeline don't line up but its a goofy thing to think about

@landhawk: I'm far enough removed from my one and only play of Blood Money that I'd forgotten that. It's an interesting comparison and I hadn't considered that the finale was the first time you could not kill anyone either.

I guess my thing with Diana is more, benevolent assassin or benevolent illuminati aside, I just I don't see what we have about her specifically to lead us to accept that she's like a "good person." She's good to 47, but even that has it's motivations, originating in a desire to go up the ranks of the ICA. You know, that company that murders people for money.

I guess throughout the series, even before you discover Providence you are murdering "bad people" but nothing about the ICA says the *only* murder bad people right? Surely Diana and 47 have run ops to kill innocent people for cash/political reasons? This all assuming the "canon 47" only kills his targets during missions like a professional. Maybe I'm a cynic but it seemed to me like they wanted a feel good ending for a lady who kills people for money and a hitman. LIke.... they are what they are.

I've finished it so I'll dredge this up.

What else are they gonna do? Find Jesus?