If it doesn't have that little SteamOS icon at the end, it usually means it does not support Linux/SteamOS. They then replaced that with the SteamOS logo, which is basically the Steam logo in a coloured circle. The problem is, Valve originally used the Linux 'Tux' icon to show Linux compatibility: Hopefully this will help clear it all up. I still see a surprising amount of confusion from people on what Steam games work on Linux.
