Been around since early 2000s, there's an international official server, and hundreds of private servers n stuff. You kill squishy little pink things until you can kill squishy little green things.
Differences in servers tend to be.. Private servers have varying exp/drop rates, custom items, different level caps, yada yada.
The main point of the game is to collect cute and rare hats, obviously. But if you're lame and don't care for that you can do some guild wars or hunt bosses for their rare items / cards, and break items upgrading them.
This post was edited by Fizzle on Mar 5 2016 01:27pm