Spiral Knights: the best ever MMO is back again!

A long, long while ago I, along with some internet bros, came upon this beautiful, fun, (and I almost never use this word) cute MMO. It was up for a month or two for a beta test and now it's back apparently with lots of new features, but only to certain individuals that received an invite via email that I was lucky enough to be a part of.  It's a great co-op dungeon crawler with lots of fast paced gameplay and an art style reminiscent of Zelda Wind Waker.

I've only just started playing the new version today and so far there's a bunch of new features like throwing deadly vials and collecting heat dropped from enemies to upgrade weapons and armour. And there's probably a lot more I haven't seen yet.