This game is very simple, but pretty great. I love the simplicity and everything, and only have a few small suggestions.
1. A back button on the password scene to go back to the main menu would be nice, instead of having to press escape when you want to go back.
2. Perhaps add a "how to play" or tutorial into the game, or at least the description. I went into the game having to figure out the mechanics for myself with no context.
Other than that, it's a beautiful game, very simple and very fun and challenging. Great work!