According to the developer, Reaktor is a program that lets you create entirely new instruments suitable for composing music, creating sounds, and so on. All this sounds pretty good; however, I couldn't find if this is true or not.
First of all, the program is not intuitive at all; you need to read the manuals before trying to do something with the program. Also, it asks you to install different modules such as Block Base and Factory Library to start trying the program. Nevertheless, I did install them, and the program still prevented me from doing anything.
I understand that it is a demo version of the program, but I couldn't watch or create a demonstration of the program's capabilities, despite that, I followed the respective instructions.
Another weird thing is that the installation file is an .iso file. Although these files are intended to create images on an empty CD or DVD, you can open them using other programs such as WinRAR and install the program from them.
Please note that the demo version only works for 30 minutes each time.
Also, to download the program, you will need to provide a valid e-mail address.
In sum, if you have used this program before and know exactly how to work with it, you may find useful this demo (which you probably don't need since you already know the program). If not, you may find it a waste of your time.