This software comes in Modules. Some are optional, and some are required.
The idea is that you will not need to download and install a monster bugger, end up only using some of it, but having to cop with all the crap you don't like. Instead, according to your needs, download and install only the required and needed modules.
You have to make sure of the dependencies of those modules though, which is given on the download page of the Web site.
There are 3 packages available at this time:
Aloha (which is called $kahuna) and Hash_Utils are the two required built-in stone of the software: You have to install those two modules before doing anything.