STEAM CD KEY : Use the Steam Key Code on Steam Platform to download and play Zenodyne R. You must login to your Steam Account or create one for free. Download the (Steam Client HERE). Then once you login, click Add a Game (located in the bottom Left corner) -> Activate a Product on Steam. There type in your CD Key and the game will be activated and added to your Steam account game library.
Standard Edition. Read the store description to know the content.