This is a lovely little game. Its long enough to feel worthwhile, but not so long it outstays it's welcome. Yuki is a cute protagonist and the dialogue manages the balance between amusing and serious. None of the puzzles are overly complex (although the key puzzle had me stumped until I experimented), but there are still plenty of opportunities for an early game over.
There are also four different endings depending on the choices you make towards the end of the game. Remember to save often, and pay attention to your surroundings!