This is the third time we've played MOM, and nobody has yet won. Neither the keeper nor the players manage their win condition before the time runs out. Mostly it's because of things like these:
At a certain point in the third story, you're told that a door cannot be unlocked unless you know the "magical phrase". This refers to a card, hidden elsewhere. But there's also a time-sensitive card which gets read at one point that reveals a "magic phrase". This is confusing, and led to us having to backtrack significantly in the game.
Also, is it just me or does it seem like there's a very specific order in which things have to go in order for the players to win? The game banks a lot on players managing to guess correctly the order of events as they go through the game, and there really is no time (see my first line) to waste. I also think the game might be unwinnable if you aren't able to guess the correct meaning of some ambiguous cards.
Example: at a certain point you have a (I think) silver key in your hand, which tells you that you can discard it to open a 'locked' door. OK, so the players use it to get into a room. Then a room or two later, they find a lock that REQUIRES said silver key, and no others. Is the game now unfinishable? Apparently, since the room it opens gives you access to a locked cabinet elsewhere, which holds the win condition for the players.
Similarly, when using a crowbar against a zombie, it broke. This was before the manhole was opened, which made it a much less interesting game all of a sudden. As keeper, I exercised narrative executive power and allowed the players to pry open the cover with their crucifix (which makes about as much sense as breaking a crowbar on a rotting zombie). I think leeway on the keeper's part is required for the story to be told with any justice.
I'm all for narrative in board games, but it seems like the moment you introduce elements of language into play, there's more interpretation than the rules can really handle. The conditions for winning are very specific, but the narrative elements make it feel more like a story or a roleplaying game, where things are a bit more fluid. Maybe the win conditions need to be more general, or there need to be options...I'm not sure. Am I out to lunch here? Are the fluidity and multiple winning conditions of a roleplaying game just not compatible with the rigidity of board game rules? Was story 3 unwinnable the way it turned out for us?