Alright, first bug. Died twice to the sewer boss and now the level is stuck. When it loads in, it loads it with every enemy i defeated before dead (killing more will perma-kill them too), all blocks i've broken before also broken and the chute down to the boss is covered by some sinister smiling blocks. I can hear the boss stomping around down there, but i can't get to him.
Loading another level does not fix this.