kaijuu is a Windows Explorer shell extension. It grants far more functionality for how to work with files and folders.
Some of the functionality kaijuu adds:
kaijuu was initially written so that game folders used by higan could be opened directly by double-clicking on them. This functionality is very similar to the way Mac OS X handles program folders that end in ".app"
It became apparent that there were many other weaknesses in Windows Explorer, so the tool grew over time to support even more functionality.
kaijuu is released under the ISC license.