[This review also contains minor spoilers for the end of The Legend of Zelda: The Wind Waker]

"It's almost time for me to go.
And with me... The last embers of this fruitless war dies out. And at last those old evils will be gone.
Once the source of evil returns to zero... A new one... A new future... Will be born.
That new world... Is yours to live in. Not as a snake... But as a man."

How does a hero die? By the hands of their enemies? Their friends? The people who believed in their legacy? Or is it by their own will to carry out a mission that no one is asking them to do?

Metal Gear Solid 4 is a game that resents its own existence. A brutal reflection on the series it's meant to send off while also criticizing it's role in perpetuating a cruel, violent digital world by an artist that is reluctantly taking on the job because he believes it's his battle alone. Old Snake is very clearly a stand-in for Kojima: a man hellbent on killing himself over a mission that could be taken on by someone else, but that'd only divert harm to them rather than make things easier for everyone (see Raiden's arc in this game). Instead it feels more appropriate for him to finish the job himself, accepting the responsibility of his actions/legacy, and then die a soldier.

Except he doesn't die a soldier, instead his father--a man whom Snake had been shaped into emulating from his inception--visits him from the beyond the grave to send a message. A plea to keep going and see his life to its natural conclusion. The old world is over and its champions have expired, there's no point in fighting anymore. It's time instead to finally rest.

When reading the opening quote, a section from Big Boss's parting words to Snake, I think about a similar speech from King Hyrule in the final moments of The Wind Waker:

"My children... Listen to me.
I have lived regretting the past.
And I have faced those regrets.
If only I could do things over again... Not a day of my life has gone by without my thoughts turning to my kingdom of old.
I have lived bound to Hyrule.
In that sense, I was the same as Ganondorf.
But you...
I want you to live for the future.
There may be nothing left for you...
But despite that, you must look forward and walk a path of hope, trusting that it will sustain you when darkness comes."

While Wind Waker is contextualized from the perspective of the youth who'll be living in this liberated world as opposed to the decaying old guard in Guns of the Patriots, they're both communicating the same idea. It's time to let go of the glories of the past so that the new generation can finally live for themselves. And where Zelda took that idea as permission to constantly evolve itself and almost never look back, Metal Gear Solid (or more specifically, Kojima) saw it as a means to permanently end the series.

There were more Metal Gear games to come in the future, of course; but this was the end of it as a legend, as a complete narrative. This is where Solid Snake died.