 This season is much darker and violent then the previous two with a  depressing ending, which got complaints from some people. The  writers of this show wrote the episode "His Masters Voice", a dark  season 2 episode. However they either got rid of the writer or  something because the Dark Ocean plotline was never finished.  Whatever the case, they went back to the roots of that episode with  this season minus the dark worlds/caves from the first tow seasons.