is not because John and his wife died, or that John got betrayed.
The real reason why it's sad is because the ending is very grim. It basically says you cannot escape your fate, no matter how hard you try.
The story goes like this:
John does stupid crap when he was young. He may have been mislead, but lived a life of crime. He tried to step out of it. The government comes in and goes oh no you don't, you gotta go do all these things for us and fix your mistake, and then you can finally go free. So John goes around doing all these menial tasks, killing people, robbing people, basically doing things that he swore he'd stop doing, JUST for the chance that his son and his wife can have a normal life and grow up without all the things he grew up with.
However, even after finishing the job for the government, he still got what's coming to him. He sacrificed himself to save his son and wife.
In the end though, we see that Jack goes down the same route that a young John goes down. A life of crime and murder. Things come full circle, and ultimately despite all the hard work and sacrifice, all were for naught. Jack still did what John slaved over the whole game to prevent him from doing.
From: THEJRod09 | #002 i dunno if i agree with you who says jack is living a life of crime and murder? he commits the one murder sure but thats more of a vengeance killing and its justified in my eyes....
I think you're missing my point. It's not about whether the killing is justified or not. What do you think happened after Jack killed the retired agent?
He either stops and get caught for murder and goes to prison for like 40 years, or he takes to the road and become an outlaw himself. Both outcomes are what John tried the whole game to prevent. John want to break Jack out of the cycle of crime. In fact, he encouraged him to read, and had hope of him being a writer.
However, at the end of the game, he ditches the whole thing and just becomes an outlaw like John.
I think most people here are too young to understand this. If I were ever murdered, I'd NEVER want my children to avenge me personally, no matter how justified the killing would be.
Like that famous proverb: The best revenge is living well.