xCept beat me to it.
The Viewer is NOT the same as a Player.
By the way, the app is pretty cool. But it should have some sort of startup page and not go straight into the game.
Phaelax, unless you plan to publish only in Windows, you will need to get at least an Android device for testing on that platform.
If you want to publish for iOS, you will need a real iOS device to test (the iPod Touch works nicely as a fake iPhone, I have one). And you will also need a Mac device to create the actual iOS app in Xcode and an Apple's iOS Developer's License (which costs $99/year). Or know someone with those devices willing to let you use them for testing and production.
Cheers,
Ancient Lady
AGK Community Tester and AppGameKit Master