Shattered Worlds received a minor update, which fixes the Steam Achievement trigger for entering the Super Secret Room #2 in Chaac's Temple, in the beginning of the game. If you have already entered the room and did not trigger the Steam Achievement, it's fine! Just reenter the Super Secret Room and the Achievement will pop up. If the game did not update itself automatically, please, right click on Shattered Worlds in your Library, then select Properties, navigate to "Local Files" and choose "Verify Integrity of Game Files..." to initiate the update.