Let's just put it this way-- revelations uses emotional content in gameplay more than any game I have ever known.
It took me a few days to beat it, mainly because I just couldn't stop myself.
SPOILER ALERT, do not read if you haven't played Assassin's Creed 4 and wish to have the story come as a suprise. I won't tell everything, but what I will tell is still a small spoiler.
In the end, Altair and Ezio are the same. Two people who grow old after a lifetime of sacrifice and uncompromisingly doing the right thing whenever possible. They fought to maintain human freedom to live by the results of their actions, not as someone would tell them to live the way the templars would.
Gods, there would be flashbacks of scenes where Altair grew into an old man who returned from exile in rags...and it was so sad because he at top speed could only walk with a limp. And was returning to kill Abbas, the current master of Masyaf, who was responsible for the death of his youngest son and wife... Abbas screamed for his assassins to kill Altair as he ascended the long way up to the gate, but the assassins would only put their fists to their hearts and say, "Welcome back, Mentor". A few people would attack Altair with swords, but he would disarm them and keep walking.
Then there is when Altair says his final goodbye to his son, and locks himself away in the vault/library, with a key that stores memories...and he records everything up till he sits down to rest...and then Ezio is there a thousand years later, with the key. Altair's body is decomposed, but still sitting on the chair regally, in full assassin garb. I just find this scene so...damn... emotional for me. Altair, the greatest of the first assassins, turned old after a lifetime of selfless sacrifices...and now he dies giving his last thoughts for the next assassin. And now, the next assassin to receive the torch is almost as old in his age, and has given just as much service for humanity, and is going to repeat the selfless cycle again...
All so that Desmond in the modern world can know that all those countless efforts were given so that he could take the torch and carry that massive burden to help save humanity in this new age...
Gods, the story couldn't be more emotionally heavy for me.
And...the game ends with a monstrous cliffhanger that leaves you breathless, and yet so furious that you can't see JUST a LITTLE bit more. Gods, it was amazing.
It's a must-play.