All I can say about this is that it was unexpected from the beginning to the end.
In my opinion, the best thing about this manga is how all the payoffs have their setups and foreshadowing, this alone made the reading very exciting.
Going from a bizarre apocalyptic story to a parallel world, time travel, and god defying related plot was very ambitious.
The ending was kinda ok, it wasn't that good, but atleast it wrapped up everything. All I can say is that hardly the end of any type of storytelling media will fullfill the expectations, most of the time the run will be more satisfying than the ending.