Board Thread:Questions and Answers/@comment-25222488-20150227031543/@comment-6697950-20150303204713

Depends on how they change the story. There were at least four episodes in season 1 that had more or less changed some details... or major parts of the story. Episode 2 of season 1 is a prime example of a multiple major plotline changes in the same episode (though that technically was an episode made before the author decided to make a series out of the story that he wrote for the episode to reduce the timeskip). But in season 2, they avoided any more noticeable changes (though they still can't get their dates right) in the plot, aside from the usual unnecessary plot omissions to save screentime. So, I currently see a growing tendency to avoid deviating from the original plot too much. However, Alicization DOES have timeskips again, so who knows. Heck, even the light novel added in some filler content as compared to the web novel. But the expressions "wont exactly tell you everything" or "wont disclose everything to leave surprises" are inaccurate, since I doubt that the author plans most of the fillers in advance. He makes stuff up on the way if he needs to, but that doesn't mean that he kept something hidden until that point. I only remember two scenes where he actually revealed details that he later expanded upon in a side story, but it's arguable how much he had that planned in advance.