Removed Cloak leaves strange patterns on screen
I went browsing in the installer package, and it looks like Cloak does some serious meddling in system frameworks.  For example, there's a lightpurple.scpt that does (among other things):

sudo mv /System/Library/PrivateFrameworks/CoreUI.framework/Versions/A/Resources/SArtFile.bin /System/Library/PrivateFrameworks/CoreUI.framework/Versions/A/Resources/SArtFileold.bin
sudo cp /Themes/LightPurple.cloak /System/Library/PrivateFrameworks/CoreUI.framework/Versions/A/Resources/SArtFile.bin


These are not changes that will reliably work as the OS gets updated.

You could do a search across the OS to find *.old.* files, but I would recommend simply reinstalling OS X.  You can reinstall the OS on top of your current system, which will replace the system files but leave your user files alone.