A great game with infinite replay and not so hard to get achievements (If you know what you're doing)
The name of both people is Altair, fitting, so players don't get confused. Somehow, the memory involves you doing random things with the ancestor to "unlock" more recent memories, even though you would think it would go the other way.
You're probably thinking "Why does he have to unlock memories?" Well, his mind can't handle the sheer POWER of the more intense memories, and so he has to ease into his memories to prevent the inevitable brain explosion.
Now, if you're looking for a game in which you can be an awesome ninja without the stereotypical Kabuki theater garbs and superlame storylines, then Assassin's creed will give you far more bang for your buck, with some of the best gameplay and replay value in a game, especially a game of this caliber.
I give assassin's creed a 10/10 for pure brilliance.