#35: Prince of Persia (Brøderbund, Amiga, 1990)

In level four, your path is suddenly blocked by a full length mirror with no way around it. Your only choice, then, is to leap through the mirror, and in doing so, create a shadow self that leaps back the other way. This moment could easily have been portrayed in a cutscene, but is infinitely more striking because you, the player, must make an active choice to not just tentatively step through the mirror but to charge at it full tilt and dive through without hesitation, to abandon yourself fully to the other side.

And this is far from the last you will see of your reflected doppelganger. Throughout the game, he serves as a thorn in your side, stealing health potions and slamming gates on you, before finally, at the end of level twelve, you come face to face, swords drawn in a climactic confrontation. But while your swordfighting skill has, by this point, been honed by the legions of anonymous guards you have dispatched along the way, you will soon find that this experience is of no use in this fight, because any wound you inflict upon your opponent will also be inflicted upon yourself. No, the only way to win this battle with yourself is to put away your sword, to realize that violence only begets more violence and to make a decision to break the endless cycle.