civmaster88:I found out that my game wasn't working because a sprite was missing. It is in a folder call "Sprite" in the content folder of my project.
When you try to publish through Visual Studio, the generated manifest will not include your Content project. This is why ClickOnce publishing is not supported. It doesn't work, they know it doesn't work, and if you want to try and make it work you're basically on your own.
The proper tools for making it work are mage.exe and mageui.exe, which are covered in detail on MSDN.