For a show based on deduction, it did not end up with airtight logic that closes all the holes in the plot in my casual opinion. I mostly dislike the multiple universes being separate thing that the show pulled in the last minute without explaining why there was no Setsu / Yuri / Manan in the universe they went to, or why the universe didn’t end otherwise due to duplicate persons existing.

Perhaps if someone rewatch it enough times they would be able to come up with some theory that is logically consistent and explains everything, but it will probably not be proof-able with only information contained in the anime.

That said, I enjoyed the ride a lot and as I said earlier, I am glad they didn’t forget Kukrushka’s plot line and even made it relevant to the solution. The show did not meet my highest hope to become a masterpiece of time loop Sci-Fi but it did not screw up the ending and disappoint either. I applaud the crew of the show for being able to make an entertaining series out of a game mechanic.

I still have questions that went unanswered though e.g. why did Manan/Kukrushka went on rampage that one time, but not in any other loops?

I interpret it as Manan’s personality breaking due to a flawed transfer (which she mentioned was a risk) that only happens in some loops (similar to Yuri being female in some loops), but I’m not sure if it is right as she was behaving fine in this episode after the transfer. Perhaps she was just herself, but decide to have fun for one of her loops as she has many, many loops to play with.