The plugin does not require any special server functionality. As long as you run a WordPress instance with active Permalinks the code will run just fine.
This is compatible with UNIX (Ubuntu, CentOS, FreeBSD, Debian, CoreOS etc) and Windows (IIS) based systems running Apache/NGinX etc.
The system requirements (power processing and RAM) are minimum, the code is compact and well organized to provide a fast processing. It will not use more than an other regular small to medium plugin. As long as your server run WordPress without problems, this code will run just fine.
There is a minimum WordPress version required as 2.8 which is pretty much achieved by 99,9% active WordPress sites.
The plugin works along with any combination of other custom code. However there are certain plugins which may focus on a similar functionality. In such case the WP Hide & Security Enhancer will trigger a notice. Or you will have to chose between any of the two options.