$ sudo apt-get update
$ sudo apt-get install fp-units-castle-game-engine 

fp-units-castle-game-engine is installed in your system.

Make ensure the fp-units-castle-game-engine package were installed using the commands given below,

$ sudo dpkg-query -l | grep fp-units-castle-game-engine *

You will get with fp-units-castle-game-engine package name, version, architecture and description in a table

fp-units-castle-game-engine package basic information: