Yeah. I kind of wondered what was with the whales and dinosaurs and all. I mean...they've lived in the Walls for a hundred years with little to no knowledge of anything past that, so they wouldn't even know what a whale or dinosaur IS...some people I've heard speculate it's some kind of foreshadowing, but I doubt it.
I do read the manga, and yeah...the plot IS having a bit of a slower pace. I don't mind it all that much, but I do wish they'd pick up the pace just a little. We haven't seen the main cast in forever. The second season was a bit disappointing to me, but I kind of wondered if that was because I could already predict what was going on, having read and caught up with the manga and all, but maybe it was the flashbacks. There's DEFINITELY too many of them.
Is there any particular reason why the art style throws you off in the manga? Is it just that the images don't really seem complete or the shading? They kind of threw me off and I hesitated. I wasn't happy with it at first.