To my knowledge, when using the 480 steam ID, it requires your game to be shipped in the “Development” Mode. I did some testing, and I could have not done it right, but I was able to join my friend when running the development build on both our computers. But when we used the shipped build, even with the Steam_appid.txt file with the number 480 in it, we could not join eachother. Am I doing something wrong, or do you have to do all of the testing as a development shipped game until you have the steamworks SDK?