Conquer as much land as possible and try to become biggest of them all.
In splix.io you have to surround a group of blocks and come back to your own land in order to fill the group of blocks with your color.
But watch out, if someone hits your trail you die.
Also you know what's cool? It's against actual other players. Yeah that's right, that's why the lag is there. It's actually online, unlike some paper-ish apps where you're just playing against a bunch of bots.