You can uninstall or removes an installed beneath-a-steel-sky package itself from Ubuntu 16.04 LTS (Xenial Xerus) through the terminal,
$ sudo apt-get remove beneath-a-steel-sky
If you would like to remove beneath-a-steel-sky and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove beneath-a-steel-sky
If you use with purge options to beneath-a-steel-sky package all the configuration and dependent packages will be removed.
$ sudo apt-get purge beneath-a-steel-sky
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove beneath-a-steel-sky