Valve are no great fans of Windows 8, going so far as to start a project to move their Steam gaming empire to Linux. It is therefore no surprise that they do not make any compromises for Windows 8, including allowing one to pin Steam games to the Windows 8 Start screen.
That’s where FeLiZk’s Pin Steam comes in. The app allows one to select games from Stream’s service and pin either Double Wide (the default) or smaller tiles to the Start screen, and when the game is uninstalled will also remove the tile.
This app requires you to have a Steam account and to have setup a Custom URL in your steam profile. It also requires Steam to be installed on your device to launch games.
The app is $1.49 with a free trial and can be found in the Windows 8 Store here.