Almost all (compressed, as well) executables can loose from 1 to 20KiB in size, depending on several factors.
Please send some feedback :)
In the meanwhile, while the code that is built into this tool becomes something else (perhaps, it'll continue to live, depending on the public interest...), you can use it as an PE optimizer (for now, only x86 architecture is supported, that means, no x64/PE+ support).
While working with it, please feel free to run DebugView and watch some internal messages while parsing, it can be amusing :)
Notice that you'll usually have to try several times to optimize your executable, until you get desired results; when you choose an executable, configuration will change to maximum compatible one (if .NET executable is recognized, for example... those are really picky when it comes to loose some fat).)