$ sudo apt-get remove armagetronad 

Uninstall armagetronad including dependent package

If you would like to remove armagetronad and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove armagetronad 

Use Purging armagetronad

If you use with purge options to armagetronad package all the configuration and dependent packages will be removed.

$ sudo apt-get purge armagetronad 

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 armagetronad 

See Also,