DownCraft is a app which simply downgrade/upgrade your Minecraft to a desired version. Let's say a new version for Minecraft is released, and you want to test it! DownCraft is a easy way to do this, and when you want to return to normal, DownCraft does it very easy.
Downloads the files - no need for big and messy app download.
Easy interface. No need for copy/paste, program does everything for you.
Change versions as you like.
Backup system (zip compressing method)