It may be efficient in what it is doing but doesn't looks very useful given you don't seem to have options for:
- keeping some of the cookies
- custom folders for portable programs such as Mozilla, Opera, etc.
- ...
among other things that can be deduced from the screenshots. More important, how does it find the files to delete?

There may be some documentation on the web site, but I couldn't find it because I was too lazy to authorize javascript. Dumb sites don't need javascript, and sites dedicated to software should not use javascript for navigation and access to pages, period.

A very efficient cleaner, but be very careful how you set it up; I thought I had taken care, but it emptied the shortcuts in several folders on my desktop.

If you want to be on the safe side...

1.create a restore point(as always)
2.Open KCleaner, go to option and select "expert mode"
(in this mode you can choose to "simulate" the cleaning and you can always deselect the things you don't want to be removed).
Btw the version given away here does not install any unwanted programs
(but the freeware version most likely does)

Take care.