So, I think you should probably play this game:
It's a really tiny file, literally lasts five minutes, and is easy to play. All you do is move. You really get the full message if you play through it a few times.
The rest of the post is going to be spoilers about it, so don't read unless you've played the game, or you're being a spoilsport and not playing the game at all.
The author of the game has basically come out and said that this is meant as a Memento Mori, but that the symbolism is largely up to the player to decide. You begin at what represents the beginning of your life, and the point is to travel through a maze that is very difficult to see, while accumulating points. You do this by walking and opening chests to find stars. Some chests contain stars, some don't. At the beginning you also have the option to play the game with a female companion (your wife). What will happen then is that if you travel with a spouse, your points for walking will increase, but parts of the maze will now be cut off to you.
Another thing to notice is that at the beginning of the game, your avatar is at the left of the window. As you progress, he moves closer and closer to the right edge, inevitably, the end of life. Also, notice that when you start, you see layers of most of the rooms you will explore throughout the game in front of you, and at the end, those layers are behind you.
Yes, you can play as a true gamer and try to accumulate as many points as possible, but the point here, I think, is does it matter? Not that I'm saying it doesn't, but in a normal video game, you're accumulating items, points, levels because you know at the end there will almost always be some huge payoff. In Passage, there is no payoff. You have your points, but you're dead, and it's up to you to decide whether you made the right decision, or whether you would have rather explored, taken the spouse along, gone a different way. There's no right or wrong way to play Passage, and yes it's almost always depressing, but I think it's a really good example of how to tell a story in a way that uses no words and involves complete interactivity.