Cannot uninstall game - no uninstaller?

-refunded game
-game removed from steam library (so no way to uninstall it through steam client)
-went into control panel to uninstall
-says it was successfully uninstalled then disappeared from the control panel
-Steam\steamapps\common\sandstorm still has all the game files


What is the correct way to uninstall this? Some say deleting the game folder does not delete all the files.
What do?

Vicious - 7 hours ago

Sandstorm open beta disappeared from my library and my control panel, but remains in steam apps folder taking up over 35gb of space. Manually deleting this will still leave the registry entries. I shouldn't have to manually delete reg entries to uninstall something.

Sir, are the developers aware of this?

Yep, we're aware of it and looking into it.