We played with 4, which is noted by most as the optimal number, and I can see now why that is. The game would absolutely work fine with 2 players--each would play two characters, and you'd still get a great experience. But because of the mechanics of the game, 4 players could be a slightly better experience, I think.
As one example (no spoilers, obviously): in game, you visit locations represented by cards. When you visit one, you get to examine its card--but only you. You can (and should) describe what you see to your fellow players, but you can't show them the card or read it word for word (if it has text). With 2 players, you would be viewing more cards, since you would be playing 2 characters instead of one.
In a way, this might make it easier. But it could also make it more difficult--when we played, the other players periodically interpreted clues in ways I didn't, and we discussed as a group how best to proceed. The collective decisions were sometimes more successful than ones I might have made with just one other person to bounce ideas with.
That said, if 2 players is your only/best chance to play, then by all means, play it : )