To test the game on the simulator or device, you will need the Windows Phone SDK. This can be downloaded from http://dev.windowsphone.com/en-us/downloadSDK.

Once you go to this link, under SDK 8.0, click on the Download button, as shown in the following screenshot. This will download WPexpress_full.exe.

Double-clicking on Install will initiate the installation of the SDK and install it on the machine. If Hyper-V is turned off, after restart, go to the system BIOS and enable virtualization to enable Hyper-V.

Hyper-V is a virtualization tool that enables you to run the Windows Phone 8 simulator on your PC. Like any virtualization tool, it will use some part of your current system resources such as hard disk, processor, and RAM and show you how the game/application will run on the device. But since it uses your current system resources, it is like running one system inside another system, so the result won't be exact, as it would be on the device, but at least it will give a good idea of how the application/game will look on the device. For actual testing, I still would recommend using an actual device.