Why to download it? Play it On-Line
You can play it offline
It contains all skins and levels
Put a light version in your blog or web
The downloading of a new version is totally compatible with the previous one. That is to say, that if you were playing in level 17, when decompressing the ZIP and opening the game, the game will be started again where you had left it. That yes, you will have of more levels, or some new skin.
I suggest you you visit this page from time to time to be up-to-date with the last version