Even when you don't get a high score, you've still made an attractive playing field, plus there's the soothing background music and sound effects. This stuff's like crack!
The goal is to simply make as long of a continuous path as you can. Depending on the game options you choose (and if you're on the free version or not), you either have a limited size of a playing field and unlimited markers, and you just try to fill the confined space without hitting a dead end. And in my favorite version, you have a limited amount of markers to put down in what I assume is an unlimited playing area. The only problem is the longer the path you make, the harder it is to gain additional pieces (you get another playing piece each time your path crosses one of the flowering cherry trees). Run out of pieces and it's game over, man!
Oh yeah, I'm playing it within my Chrome browser. I'm assuming you need to be running Chrome, but I honestly haven't tested this. Why would I take the time to do that when I can keep playing my game?!
Seriously, give it a try and see if you're not hooked. Don't worry, it's free until you want the expansions. I'm sure you can resist. ;-)