So many people say that Diebuster can't beat the original and I agree. It doesn't beat it. It embraces it. It elevates it. It champions it. And that's why I personally think Diebuster is one of the best anime sequels out there. It succeeds precisely because the original was already so amazing. To say that one is better than the other is simply doing both a disservice.
To elaborate, Diebuster expertly expands on the mythos of the original series while being 100% respectful to the original material. The older characters don't need any more development because their stories are already finished! So many sequel projects fail to realize this simple fact. No, we don't need Noriko to suddenly become all angsty. Why risk altering fans' perceptions of a character that is already well-loved and well-established? Instead, Diebuster is able to please fans by keeping the same tone and feel while remaining fresh by embracing new characters and ideas.
Speaking of ideas, Diebuster does take its time with the reveals. However, once the pieces start falling into place, no Gunbuster fan will be able to resist grinning from ear to ear. Diebuster is not only logically consistent with the original series, everything makes perfect sense once everything is revealed.
Now, let's talk about that ending. That ending is one of the most brilliant endings in anime sequel history. Suffice to say that it encapsulates everything good about this series I've mentioned thus far in one simple scene.
All in all, Diebuster is a phenomenal sequel anime. While I'd say that your ability to enjoy it fully is predicated on having seen and enjoyed the original series, it doesn't contain blatant yet esoteric fanservice for the express purpose of preying on fans' collective nostalgia. Neither does the series retread the original nor does it disrespect it. Both series complement each other perfectly, with Gunbuster being Diebuster's loving onee-sama.
