This is a collection of tools you may like if you are interested on reverse engineering and/or malware analysis on x86 and x64 Windows systems. After installing this toolkit you'll have a folder in your desktop with shortcuts to RE tools like these:
You don't. Obviously, you can download such tools from their own website and install them by yourself in a new VM. But if you download retoolkit, it can probably save you some time. Additionally, the tools come pre-configured so you'll find things like x64dbg with a few plugins, command-line tools working from any directory, etc. You may like it if you're setting up a new analysis VM.
The *.iss files you see here are the source code for our setup program built with Inno Setup. To download the real thing, you have to go to the Releases section and download the setup program.
Check the wiki.
I don't know. Some included tools are not open source and come from shady places. You should use it exclusively in virtual machines and under your own responsibility.
It depends. The idea is to keep it simple. We won't add a tool just because it's not here yet. But if you think there's a good reason to do so, and the license allows us to redistribuite the software, please file a request here.