I don’t know if this is a good game or not, but I’m sure “best Linux game ever existed” is just a wishful thinking ;-) There are lots of good games on Linux, for example The Battle of Wesnoth, among others.
Tour title is click-bite… Not a very good practice ;-)
In Catalonia, Europe, with a population of 7,5 millions, most secondary public schools use Linkat, a Linux distro based on Debian/Ubuntu:
http://linkat.xtec.cat/portal/index.php
That means there are thousands of children using Linux ;-)
And there are some other countries in Spain with their own scholar Linux distro.