@micahflee There is also ssss, which is a command line implementation. Not a GUI, but easy to use and still suitable for many people. It's available in many GNU/Linux distros.

My initial concern with Sunder is that it has a huge number of dependencies, along with a complex runtime, which drastically increases the attack surface and the possibility of things going wrong. It also makes it very difficult to audit the system as a whole.

Thanks for sharing, though; I'll submit comments as requested.