Basically the same gameplay as the old galcon that I've played many years ago, with some improvements. Except now it is free.

For those that don't know old galcon - a simple space battle, where you conquer planets with fleet of your ships. No upgrades, no ship development, none of the complicated stuff. Just an initial fleet for all players and bunch of neutral planets on the field. Battle usually lasts few minutes, then you can just start a new game. Nice simple game for occasional battles :)