>>101072127Protagonists had good chemistry and a fun relationship, the fakeout villain was fun with a great rags-to-riches arc and interesting backstory, the real villain was diabolical and always a step ahead with his keikaku and voiced well by a notable actor.
The idea of travelling to new dimensions is fun and opens the series for lots of potential plot developments.
Unfortunately it went downhill when they killed off Toffee for a weaker, more uninteresting villain, didn't use Eclipsa to her full potential.
More than that they yanked apart the two protagonists and destroyed their good chemistry to try and recapture the angst and relationship stuff that people liked from Season 2, unfortunately failing due to the hamfisted way in which they strained Marco and Star's relationship, changing their very characters to do it.
The 3rd season also had a "healing the monster-mewman divide" plotline that went nowhere and criminally underutilised Ludo, all to wrap it up with something that looked like it could be interesting (Miss Heinous as Eclipsa's daughter) but turned out not to be.