Whoa, pretty bad that Steam is now required to play multiplayer in Blockland.
I have re-enabled key authentication, with the limitation that it will not work on new IP addresses. That means you can log in and play as normal, but only if your IP is the same as it was a few days ago (or the last time you logged in).
What does this mean if you want to play Blockland in a house of your friend, partner, family members, etc?