The programming interface that Hurd provide is similar to that of any modern operating system. So, it can run pretty much any program that runs on Linux or BSD, but you have to port it. Doom is no exception. If you cannot find a video of Doom running on Hurd on YouTube, it doesn't mean that Hurd can't run Doom.

Hurd is sure not a successful project, but it is a capable operating system. Linux comes with a lot of device drivers for all sorts of hardware, so Linux nowadays can run almost everywhere. But that is not the case with Hurd because only a small number of people are contributing to this project and it is largely eclipsed by success of Linux. But it is an extensible system so if you want support for a hardware, you can develop a driver for it. But nobody is interested.

If you haven't seen Hurd running a desktop, I will introduce you to Debian Hurd (https://www.reddit.com/r/linuxmasterrace/comments/18i6e94/de...). It is a Debian distribution with Hurd as the kernel instead of Linux. It comes with Xorg and you can install XFCE, OpenBox. Basically, you can install any desktop that render on CPU. Desktops like GNOME and KDE need more infrastructure. They relay on modern GPUs and uses direct rendering. In Linux, we have DRI and Mesa for this. As of now, Hurd doesn't have any such infrastructure. As I have already said before, a lot of people are contributing to Linux and only a handful of people are contributing to Hurd.

If it can run nginx and node.js on a VPS it could be a nice alternative to Linux.