I am creating a launcher/updater for my Unity game, and I'm using a Cocoa/AppleScript type project so I can download updates from my web server and launch them, but I have no idea how to do that, I would also like to implement a progress bar that shows people the progress of the download/update.
The OS is OSX 10.10 (Yosemite)
For an app update, if it is not in App Store, the option that you have is Sparkle (http://sparkle-project.org/). if it is a single app, you will be able to use sparkle directly. If your product is a complex one with installer (pkg etc), you can tweak sparkle a bit to support that.