What's unique about this game is the design: the game just feels very smooth that even when you lose and begin a new game, you will not feel any discontinuity in the game. The smoothness is also evident in the motion of the rabbit following the cursor of the mouse just the way you will mean it to do. I didn't find the game very easy with the average try taking about a minute, but there are many videos all over the internet of people reaching incredible scores. The highscore is stored locally in the cache of the web browser. What's important is that it is a quick game to play, so you can pick a try or two in between your normal daily activities. The music is just exceptional, and together with the ease of gameplay are important factors of this game's popularity.
It is a simple, well-designed and stands as a proof that game-development is another form of art. While this type of games is usually called time-wasters, I didn't feel that wasted anytime at all playing it, because it was fun.