Ugh, problem after problem
now that blockland works it won't save my preferences (settings), the way to fix this is to download the blockland launcher demo, put it in the steam folder and re-name it to "Blockland" but the launcher remembers my preferences so it's "stuck" on fullscreen mode again.
Go to your Blockland folder, then go config, then client and open up the prefs.cs with the mac equivalent of notepad
There search for the pref "Fullscreen" and change it to:
$pref::Video::fullScreen = "0";
You should then be able to play again.