Very relaxing, the 28-level demo is still a lot to work with for free, and when I did it all over again a few months later, it's still as fun, and challenging too. I'd say you can complete this demo in about 1-2 hours.
I only have played the demo but i think this is a gret and beautiful game.
The only bad thing is that it dosen't have a tutorial to show how to play to the begginers
