This is one of the few times I've seen the OP almost entirely synchronized to the singers. Though "Oshiete A to Z" had it in some parts. The show also has an art style that's pretty distinct for itself, so it has that in its favor.
As for the show itself, the CGI is really obvious in some parts, but I can let it slide. The show had enough absurdity and jokes (including a scene-long innocent innuendo at the end), that it almost fully divorced itself from reality. Now to see how much further it can take that. Good stuff.
The ED is in sharp contrast to the rest of the show, but the soothing effect might be needed after the show goes all wild.