The episode was too rushed in my opinion and they could have, at least made a two part episode of it to explain the powers and the battle could have been bit more interesting.

Besides the new powers it was really dull and uninteresting , Rena Rouge came back and it was only used as a plot device

Actually, I don't understand, why they called Rena to catch the Panthers if Cat and Ladybug actually could handle it good like in Animan. About Ondine's akumatization I think it was a bit too odd, just because Kim was going to the movies with Chloé and not keep playing with her to eventually find out her crush on him,

I thought it was okay. I was so excited for the new powers and stuff and I thought it was interesting. I also loved that c(h)at Noir finally met Master Fu. I also loved the scene with nooroo and hawkmoth for character development aspects (Though I felt so bad for nooroo, who I’m pretty sure is my favorite Kwami) and the scene with Adrien and Plagg was so sweet and gave a lot of characterization that I enjoyed. (Even though the whole scene before Plagg was saying all those sweet things where C(h)at Noir was thinking about quitting seemed very uncharacteristic of Adrien. I mean it’s obvious he loves being c(h)at more than anything (besides his lady) so it just felt odd) But as many of you said, I felt like it was kinda rushed and it was just weird. He arena Rouge thing was weird but honestly I don’t care to much. They could’ve called her for something that happened before the panthers and she just stayed for a little bit to help with that, or some other reasoning.

There were both positives and negatives to this episode.