A wonderous title and an unchallenged classic. The overly positive reputation and dare I say cult-like following this game has is completely well-earned. The major flaw I could name in relation to this game isn't even in the game itself. That being the lack of communication between the development team and the community.
The lack of updates also contributes to this, however this is much easier to explain, considering the history of the development of the game and how many people have come and go, resulting in difficulty in making changes to the code and from then on the game.
TL;DR: Great game for what it aims to be. But it has grown too big and complicated to be changed and from then on be bettered.