It's just like all Urasawa work, it's his trademark, He doesn't know how to end his story. Yeah I get that,in the end, arts is the thing that will save humanity, because it will give use hope to built a better mankind. But do we really have to go to 165 chapter with this time travel, spy, mythic stories to go to that conclusion???? Even 20-21 century boys and pluto have the same treatment (I haven't read the monster, soon).
In my opinion, the three bat were the representation of the three Hinduism main Gods, Brahma, Vishnu, and Shiva. Creator (the one in the moon), protector and destroyer (white and black). But does it means anything? Not really, they were just trolling humanity all along. I don't get it, no ones get it.
The Billy bat, Chuck, and Billyland of course is a jab to Mickey Mouse, Disney, and Disneyland. Maybe soon Disney will buy some petrol and water refinery company? Only times will tell.
Still I always enjoy this branching out story. The branches are more short and have more intersection than the other comics before, so I didn't find it frustrating to read a whole new character and plot
That's it I guess 7.8/10